Circumcision,  Sexual Functions, and Penile Sensitivity

Introduction

Last updated: April 2020

What more effective way can there be to discourage parents from circumcising their sons, or to bring angry, motivated new recruits into the intactivist movement, than to convince them that circumcision ruins one’s sex life? So it is no surprise that intactivists put much time and effort into portraying foreskins as wonderful erogenous pleasure centers, the source of all things enjoyable. They argue that circumcision removes this most erogenous part, leaving the remaining organ deadened, dysfunctional and about as sexually enjoyable as a broom handle dipped in cement. Men circumcised as adults will know what nonsense this is, but many men were circumcised as infants, so have no experience to draw upon. If they fall for this narrative they will be at once distressed, depressed, and enraged at the imagined injustice of it. Similarly, parents who naively believe the intactivists’ propaganda, will not want to inflict these supposed harms upon their child, so will be deterred from having him circumcised, or will suffer a massive guilt trip if they have already done so. Intactivists have even set a target: 600,000 resentful circumcised U.S. men, believing that if they can achieve this number of dupes the resulting hue and cry will bring about what they yearn for – a ban on infant circumcision. This was stated on one of their websites in 2014: https://notyourstocut.com/2014/12/06/the-biggest-risk-factor-and-the-quickest-path-to-change/

The psychological effect on those hoodwinked by bogus intactivist claims cannot be understated. Indeed, the man in the photo in the link (Jonathon Conte) suffered years of depression as a result of falling for intactivist propaganda that he was sexually crippled, damaged goods, and missing something wonderful. Tragically, he took his own life in May 2016, aged 34. Just over a year previously another young man (Kevin Cagle, aged 20) also committed suicide. Again this was due to needless distress at having been circumcised: https://www.facebook.com/KevinMidori?fref=ts  (Scroll to 1 April 2015). Parents who have fallen for the intactivist narrative also report distress, even suicidal thoughts. Intactivists even have a term for them: “regret parents”.

So effective is this strategy that entire sections of intactivist websites are given over to peddling false claims of damage to sexual function. Their literature is full of assertions about nerve endings, sensitivity, foreskin functions and so forth. Often this is backed up by “scientific” literature citations, giving an appearance of scientific credibility. But a good skeptic will be familiar with the tricks of the pseudoscientific trade – cherry-picking, misrepresentation, passing off speculation as fact, over reliance on personal testimonies, ignoring the criticisms by experts, etc. All of these academic sins are committed by intactivists in their quest to traumatize circumcised males and scare parents into not circumcising their sons. Such a quest is dishonest, cruel, and utterly unethical.

The science is clear. At the time of writing (December 2019) there are, on this topic, a total of 59 studies and 4 systematic literature reviews incorporating two meta-analyses. The great majority show that circumcision has no adverse effect on sexual pleasure, function or satisfaction. (https://www.facebook.com/CircumcisionResource/photos/a.735986419837365.1073741827.712201812215826/913150462120959/?type=3 ).

Significantly, these include studies of men with healthy foreskins who were then circumcised, so they have before and after experience without the confounding issue of pathology. After all, if a man was circumcised because he had problems with his foreskin, it would be unsurprising if he then reported an improvement. Conversely, sexual problems associated with foreskin pathology (particularly if the glans had become damaged, or the man had developed psychological issues) may linger after the operation. Either situation could be a source of confounding so, even though such studies commonly show more improvement than the converse following circumcision, they are excluded from the assessment that follows.

There are even studies, including randomized controlled trials (RCTs) of men circumcised in adulthood, that show that circumcision imparts a modest improvement in pleasure, function and satisfaction for both participants. In fact, all the best quality studies, in the top four tiers of the hierarchy of evidence, (https://online.manchester.ac.uk/bbcswebdav/orgs/I3075-COMMUNITY-MEDN-1/DO%20NOT%20DELETE%20-%20PEP%20Quality%20and%20Evidence/QE-PEP-HTML5/AN-232E8560-4F14-1254-C272-DE02E63DB32D.html ) find either no adverse effect, or an improvement following circumcision.

As of December 2019, these high-quality studies comprise:

One case-control/cohort study: Nordstrom et al. (2014).

Five cohort studies: Brito et al. (2017); Cheng et al. (2014); Feldblum et al. (2015); Galukande et al. (2017); Yue et al. (2014).

Three RCTs: Kigozi et al. (2008); Krieger et al. (2008); Kigozi et al. (2009) – the last studied the female partners of circumcised men.

Four systematic reviews: Morris & Krieger (2013); Shabanzadeh et al. (2016); including two meta-analyses: Tian et al. (2013); Yang et al. (2018).

In addition to the above, a recent systematic review of women’s preferences found that most women, even in non-circumcising cultures, prefer the circumcised organ for reasons of appearance, cleanliness, health and sexual pleasure (Morris et al, 2019).

The strong scientific research is routinely ignored as the intactivists cherry-pick a handful of weak studies purporting to show the opposite. They supplement these with a collection of spurious claims that foreskins contain 10,000, 20,000, 70,000 (take your pick) erogenous nerves, serve 16 functions, facilitate intercourse, and that one cannot enjoy a full and satisfying sexual experience without one. And, of course, personal testimonies alleging harm caused by circumcision. At least some of those testimonies are known to be fabrications (http://circfacts.org/sloppy-logic/#slog22 The “David J Bernstein” hoax).

Most of the favourite studies of the intactivists have been severely criticised, whether in the peer-reviewed literature, or by well-informed skeptics on-line. The Table below lists some of the intactivists’ favorite studies (these tend to be the same few over and over again), the critiques of these and, in some cases, responses to those critiques. These last can be illuminating as the authors concede some points, misrepresent others, or, having no answer, resort to personal attacks on their critics. The rest of this section is given over to debunking specific myths relating to sexual function, pleasure etc.

Intactivist article Key claims Critiqued by Key criticisms
Bollinger & Van Howe (2011)

Bollinger & Van Howe (2012)

 Circumcision causes alexythmia, need for Viagra

Defending their study, concede potential for bias

 Morris & Waskett (2012) Selection bias, alternative explanation
Boyle (2015) Critique of a review finding no adverse effect Morris & Krieger (2015) Criticisms are unfounded
Bronselaer et al (2013)

Bronselaer (2013)

 Increased sexual dysfunctions

Defending their study, concede selection bias

 Morris et al (2013)

Wolfe et al (2014)

Wang et al (2013)

 Selection bias, statistical errors

Internal contradictions

More evidence for selection bias
Frisch et al (2011)

Frisch (2012)

 Slightly increased sexual dysfunctions

Defending their study, personal attack on Morris

 Morris et al (2012)

King (2011)

Meyrowitsch (2019)

 Selection bias, alternative explanations

Tiny effect, results “over-analysed”

Alternative explanation
Hammond & Carmack (2017) Adverse effects on sexual function, men unhappy with being circumcised Bailis et al (2019) Selection bias, no verification, speculations about “function” unsubstantiated, scientifically worthless.
Kim & Pang (2007) Masturbation less enjoyable Willcourt (2007) Methodological flaws, sums don’t add up
O’Connor & Narvaez (2015) Psychological damage Gross (2019) Citations do not support the claims
O’Hara & O’Hara (1999) Women prefer non-circumcised partners Gross (2018) Methodological flaws, selection bias
Sorrells et al (2007)

Young (2007)

Van Howe (2017)

 Foreskin most sensitive part, glans desensitised

Defending Sorrells

Defending Sorrells

 Waskett & Morris (2007)

Morris et al (2017)

Ibid

 Statistical & methodological flaws

Young misinterprets the criticisms

Van Howe attacks a straw man

References
Bailis, S.A., Moreton, S., Morris, B.J. (2019) Critical evaluation of a survey claiming “Long-term adverse outcomes from neonatal circumcision.” Advances in Sexual Medicine, 9(4). On-line: http://www.scirp.org/Journal/paperinformation.aspx?paperid=95051

Bollinger, D., Van Howe, R.S. (2011) Alexythmia and circumcision trauma: A preliminary investigation. Int. J. Men’s Health, 10(2), 184-95. https://www.questia.com/library/journal/1G1-271664388/alexithymia-and-circumcision-trauma-a-preliminary

Bollinger, D., Van Howe, R.S. (2012) Preliminary Results Are Preliminary, Not “Unfounded”: Reply to Morris and Waskett Int. J. Men’s Health, 11(2), 181-4.

Boyle, G.J. (2015) Does Male Circumcision Adversely Affect Sexual Sensation, Function, or Satisfaction? Critical Comment on Morris and Krieger (2013). Advances in Sexual Medicine, 5, 7-12. https://file.scirp.org/Html/1-1990065_55256.htm

Brito, M.O., Khosla, S., Pananookooln, S., Fleming, P.J., Lerebours, L., Donastorg, Y., Bailey, R.C., (2017) Sexual pleasure and function, coital trauma, and sex behaviors after voluntary medical male circumcision among men in the Dominican Republic. J. Sex. Med., 14(4), 526-34.  https://www.ncbi.nlm.nih.gov/pubmed/28258953 (abstract only).

Bronselaer, G., Schober, J.M., Meyer-Bahlburg, H.F.L., T’Sjoen, G., Vlietinck, R., Hoebeke, P.B. (2013) Male circumcision decreases penile sensitivity as measured in a large cohort. BJU Int., 111(5), 820-7. https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1464-410X.2012.11761.x

Bronselaer, G. (2013) Reply. BJU Int., 111(5), E270-1. https://onlinelibrary.wiley.com/doi/full/10.1111/bju.12128_10

Cheng, Y., Wu, K., Yan, Z., Yang, S., Li, F., Su, X. (2014) Long-term follow-up for Shang Ring male circumcision. Chin. Med. J. (Engl.), 127(10), 1879-83.  https://journals.lww.com/cmj/fulltext/2014/05200/Long_term_follow_up_for_Shang_Ring_male.16.aspx

Feldblum, P.J., Oketch, J., Ochieng, R., Hart, C., Kiyuka, G., Lai, J.J., Veena, V. (2015) Longer-term follow-up of Kenyan men using the ShangRing device. PLoS One, 10(9), e0137510.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4569077/

Frisch, M., Lindholm, M., Grønbæk, M. (2011) Male circumcision and sexual function in men and women: a survey-based, cross-sectional study in Denmark. Int. J. Epidemiol., 40(5), 1367-81. https://academic.oup.com/ije/article/40/5/1367/658163

Frisch, M. (2012) Author’s Response to: Does sexual function survey in Denmark offer any support for male circumcision having an adverse effect? Int. J. Epidemiol., 41(1), 312-4. https://academic.oup.com/ije/article/41/1/312/647866

Galukande, M., Nakaggwa, F., Busisa, E., Sekavuga Bbaale, D., Nagaddya, T., Coutinho, A. (2017) Long term post PrePex male circumcision outcomes in an urban population in Uganda: a cohort study. BMC Res. Notes, 10, 522.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5663120/

Gross, A. (2018) Sex as the researcher intended it. On-line article: https://www.circumcisionchoice.com/single-post/Ohara

Gross, A. (2019) Does circumcision cause psychological damage? On-line article:
https://www.circumcisionchoice.com/single-post/Psychological

Hammond, T., Carmack, A. (2017) Long-term adverse outcomes from neonatal circumcision reported in a survey of 1,008 men: an overview of health and human rights implication. Int. J. Human Rights, 21(2), 189-212. On-line: https://www.tandfonline.com/doi/abs/10.1080/13642987.2016.1260007?journalCode=fjhr20 (Abstract only).

Kigozi, G., Watya, S., Polis, C.B., Buwembo, D., Kiggundu, V., Wawer, M.J., Serwadda, D., Nalugoda, F., Kiwanuka, N., Bacon, M.C., Ssempijja, V., Makumbi, F., Gray, R.H. (2008) The effect of male circumcision on sexual satisfaction and function, results from a randomized trial of male circumcision for human immunodeficiency virus prevention, Rakai, Uganda. BJU Int., 101(1), 65-70.  https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1464-410X.2007.07369.x

Kigozi, G., Lukabwe, I., Kagaayi, J., Wawer, M.J., Nantume, B., Kigozi, G., Nalugoda, F., Kiwanka, N., Wabwire-Mangen, F., Ridzon, R., Buwembo, D., Nabukenya, D., Watya, S., Lutalo, T., Nkale, J., Gray, R.H. (2009) Sexual satisfaction of women partners of circumcised men in a randomized trial of male circumcision in Rakai, Uganda. BJU Int., 104(11), 1698-701.  https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1464-410X.2009.08683.x

Kim, DS., Pang, M.D. (2007) The effect of male circumcision on sexuality. BJU Int., 99(3), 619-22. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2006.06646.x

King, M. (2011) Interview with Professors King & Frisch.  “Women’s Hour”, BBC Radio 4, 21 June.  On-line: http://www.bbc.co.uk/programmes/b011zzh8

Krieger, J.N., Mehta, S.D., Bailey, R.C., Agot, K., Ndinya-Achola, J.O., Parker, C., Moses, S. (2008) Adult male circumcision: Effects on sexual function and sexual satisfaction in Kisumu, Kenya. J. Sex. Med., 5(11), 2610-22.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042320/

Meyrowitsch,D. (2019) The myth of male circumcision and sexual dysfunction (Letter). The Guardian, 14 July. https://www.theguardian.com/society/2019/jul/24/the-myth-of-male-circumcision-and-sexual-dysfunction

Morris, B.J., Waskett, J.H. (2012) Claims that circumcision increases alexithymia and erectile dysfunction are unfounded: A critique of Bollinger and Van Howe’s “Alexithymia and circumcision trauma: A preliminary investigation”. Int. J. Men’s Health, 11(2), 177-81. https://www.thefreelibrary.com/Claims+that+circumcision+increases+alexithymia+and+erectile…-a0305192594

Morris, B.J., Waskett, J.H., Gray, R.H. (2012) Does sexual function survey in Denmark offer any support for male circumcision having an adverse effect? Int. J. Epidemiol., 41(1), 310-2. https://academic.oup.com/ije/article/41/1/310/647826

Morris, B.J., Krieger, J.N., Kigozi, G. (2013) Male circumcision decreases penile sensitivity as measured in a large cohort. BJU Int., 111(5), E269-70. https://onlinelibrary.wiley.com/doi/full/10.1111/bju.12128_9

Morris, B.J., Krieger, J.N. (2013) Does male circumcision affect sexual function, sensitivity, or satisfaction?—A systematic review. J. Sex. Med. 10(11), 2644-57.  https://www.ncbi.nlm.nih.gov/pubmed/23937309 (abstract only).

Morris, B.J., Krieger, J.N. (2015) Male circumcision does not reduce sexual function, sensitivity or satisfaction. Advances in Sexual Medicine, 5, 53-60. https://www.scirp.org/jouRNAl/PaperInformation.aspx?PaperID=57720

Morris, B.J., Barboza, G., Wamai, R.G., Krieger, J.N. (2017) Expertise and ideology in statistical evaluation of circumcision for protection against HIV infection. World J. AIDS, 7, 179-203. https://www.scirp.org/journal/PaperInformation.aspx?PaperID=78405

Morris, B.J., Hankins, C.A., Lumbers, E.R., Mindel, A., Klausner, J.D., Krieger, J.N., Cox, G. (2019) Sex and male circumcision: Women’s preferences across different cultures and countries: A systematic review. Sexual Medicine, 7(2), 145-61. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6523040/

O’Connor, P., Narvaez, D. (2015) Circumcision’s psychological damage. Psychology Today, On-line blog article: https://cdn.psychologytoday.com/blog/moral-landscapes/201501/circumcision-s-psychological-damage

O’Hara, K., O’Hara, J. (1999) The effect of male circumcision on the sexual enjoyment of the female partner. BJU Int., 83, Suppl. 1, 79-84. https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1464-410x.1999.0830s1079.x

Nordstrom, M.P.C., Westercamp, M., Jacko, W., Okeyo, T., Bailey, R.C. (2014) Male medical circumcision is associated with improvement in pain during intercourse and sexual satisfaction in Kenya. J. Sex. Med., 14(4), 601-12.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5388349/

Shabanzadeh, D.M., Düring, S., Frimodt-Møller, C. (2016) Male circumcision does not result in inferior perceived male sexual function – a systematic review. Dan. Med. J., 63(7), A5245.  https://www.ncbi.nlm.nih.gov/pubmed/27399981 (abstract only).

Sorrells, M.L., Snyder, J.L., Reiss, M.D., Eden, C., Milos, M.F., Wilcox, N., Van Howe, R.S. (2007) Fine-touch pressure thresholds in the adult penis. BJU Int., 99(4), 864-9. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2006.06685.x

Tian, Y., Liu, W., Wang, J-Z., Wazir, R., Yue, X., Wang, K-J. (2013) Effects of circumcision on male sexual functions: a systematic review and meta-analysis. Asian J, Androl., 15(5), 662-6.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3881635/

Van Howe, R.S. (2017) Expertise or Ideology? A Response to Morris et al. 2016, ‘Circumcision Is a Primary Preventive against HIV Infection: Critique of a Contrary Meta-Regression Analysis by Van Howe’. Global Public Health, 2017, 1-19, E-Pub ahead of print Jan 10, 2017. https://www.tandfonline.com/doi/full/10.1080/17441692.2016.1272939 (1st page only).

Wang, K., Tian, Y., Wazir, R. (2013) Male circumcision decreases penile sensitivity as measured in a large cohort. BJU Int., 112(1), E2. https://onlinelibrary.wiley.com/doi/full/10.1111/bju.12234_4

Waskett, J.H., Morris B.J. (2007) Fine-touch pressure thresholds in the adult penis. BJU Int., 99(6), 1551–52. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2007.06970_6.x

Willcourt, R. (2007) The effect of male circumcision on sexuality. . BJU Int., 99(5), 1169-70. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2007.06895_3.x

Wolfe, I., May, M., Hoshke, B., Brookman-May, S. (2014) Male circumcision is not associated with an increased prevalence of sexual dysfunction. Asian J. Androl., 16, 652-3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4104107/

Yang, Y., Wang, X., Bai, Y., Han, P. (2018) Circumcision does not have effect on premature ejaculation: A systematic review and meta-analysis. Andrologia, ePub ahead of print. https://www.ncbi.nlm.nih.gov/pubmed/28653427 (abstract only).

Yue, C., Kerong, W., Zejun, Y., Shuwei, Y., Fang, L., Xinjun, S. (2014) Long-term follow-up for Shang ring circumcision. Chinese Medical Journal, 127(10), 1879-83. On-line: https://journals.lww.com/cmj/Fulltext/2014/05200/Long_term_follow_up_for_Shang_Ring_male.16.aspx

Young, H. (2007) Fine-touch pressure thresholds in the adult penis. BJU Int., 100(3), 699. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2007.07072_1.x

“10,000, 20,000, 70,000 nerve endings”: a myth that keeps on growing

By Stephen Moreton PhD

November 2016

Anyone who follows intactivist propaganda will soon come across statements like:

“There are between 10,000 and 20,000 nerve endings compacted on to the human foreskin”.

Various numbers are bandied around –10,000 and 20,000 being the usual ones. They get combined – “10,000 to 20,000” – or used in isolation. They may refer to nerve endings generally, or to fine-touch nerve endings, or erotogenic nerve endings, even “erotogenic fine-touch nerve endings”, in various permutations. Intactivists, it seems, cannot even agree on the basic fallacies of their faith. Disturbingly, even people who fancy themselves as “skeptics” fall for it. The above quote is from “The Science of Circumcision”, an error-riddled YouTube video by U.K. skeptic Myles Power.

Like so much of what intactivists claim, this canard is all over the Internet but completely absent from the medical scientific literature, as a quick Google and PubMed search will show, respectively. When a “scientific” sounding assertion is not founded on scientific research published in scientific literature, but instead dwells on the Internet where it is endlessly repeated without supporting evidence, alarm bells should ring.

Internet myths can be tricky to track down to source, but this intrepid debunker has done it. There are actually two sources, one for 10,000, another for 20,000, although they often get conflated. I will deal with the lesser number first. 10,000 nerve endings, specifically fine-touch ones (called Meissner’s corpuscles), was a “guesstimate” by retired New Zealand pathologist, Prof. Ken McGrath, at an intactivist conference held around 1998. This was in response to a query at the conference, and was an extrapolation based on the numbers of such nerve endings in finger tips.

Initially, Prof. McGrath thought he had erred on the low side, as indicated in an email dated 13 January 2008 that was circulated on “INTACT-L”, an intactivist mailing list, in which a “Shelton” of NOCIRC-SA copied Prof. McGrath’s highly speculative calculations:

“Subject: RE: [NOCIRC-NORM LIST] Re: Media query – NOCIRC-SA response

I am taking the liberty of copying the content of a reply by Ken from NZ who elaborates on nerve endings, which makes interesting reading:

“On 15/10/2007, at 2:51 AM, Laura MacDonald wrote:

Hi All

I’d like to get a consensus on what is the most up-to-date verifiable figure on the nerve endings in the foreskin…

We’ve had some debate about the 20,000 figure in NORM-UK and I note a figure of up to double this has been quoted by some intactivists, but the figure of just 1,000 has also been used in the recent past.

Dear Laura and Colleagues,

I had better put my hand up to confess as the source of the original figure of 10,000 (it has inflated somewhat since). Some years ago I was asked at one of the symposia what I thought the figure was and came up with a ‘back of the envelope’ calculation based upon some observations I had recently done on the finger tip. When looking at transverse sections of an index finger, I noted that a Meissner corpuscle existed between each sweat duct, therefore, between each pore on the skin. Furthermore, they were arrayed along the rete ridges which are repeated in the ridges seen in a fingerprint together with the pores. So one can look at a fingerprint, see the pore circles on the ridges and know that a corpuscle exists between each one. There are about 3 pores/mm or 30/cm which, given the spacing of the ridges is about the same as the pores, means there are about 900-1000/sq.cm. This figure I then took for my quick & dirty calculation in orders of magnitude (being unable to be more precise) and said to my listeners that there had to be more than 10,000 and less than 100,000 Meissner corpuscles in each foreskin. On recalculating the density in the fingertip as above to reach 1000/ sq.cm, I am pleased to see that it is very close to the figure of 1500/sq.cm. you quote.

When we start talking about ‘nerve endings’ we enter difficult territory. What do we mean? Are we talking about fine touch receptors (the epicritical modality) or total receptors?

Let us start by eliminating free nerve endings (FNEs) which moderate pain and extremes of temperature (the protopathic modality) because they are evenly distributed without difference across all skin and number between 10–100 per axon over a field of about 1 sq.cm. (BTW: they are the predominant receptor in the glans hence its mainly protopathic sensory expression). Vater-Pacinian and Ruffini receptors modulate stretch and pressure and are few in number in the dermis/ lamina propria; we can put them aside as well. Merkel cells are thought to moderate fine touch and exist in the basal layer of the epithelium, but as they, too, are small in number and have a largely unknown activity, we can leave them out as well. Which leaves us with the Meissner receptors which are the main players in the fine touch business.

What do we make of the quoted figure of 2500/sq.cm. general receptors which I take to be the total? Adding up the other figures given leaves us with a total of 2400/sq.cm., so I can only think they have left out the FNEs. The other figure you quote is for average skin at 1300/sq.in which is 200/sq.cm. and this is a long way from the finger tip, but may be correct for the foot and other less sensitive skin.

Now to the foreskin. I will take an average size at 3 inches long (from coronal ridge overlay externally to sulcus junction internally) by 4 inches in circumference, or more simply a rectangle of 3 x 4 in.

This equals 12 sq.in = 77 sq.cm. Considering Meissner receptors only, if we accept that the outer half skin is slightly enhanced average skin at 250/sq.cm, the numbers will be 250 x 38.5 = 9625; the other half inner skin is at least as sensitive as the fingertip, so taking that as a minimum at 1500/sq.cm, the numbers will be 1500 x 38.5 = 57,750. Our pseudo-precise total is therefore 67,375. In round figures then, we may argue that the foreskin has at least 70,000 Meissner corpuscles, but on reconsidering how much more sensitive some areas of the foreskin are in comparison with fingertips (see Sorrels et al 2007), I think this figure is an under-estimate and may be closer to the 100,000 upper limit I originally specified than I was then prepared to accept.

My fingertips are about 4 sq.cm. and would have about 6000 Meissner corpuscles using the quoted figure.

With respect to the clitoris: we know that the epicritical endings are mostly found in the glans in contrast to males and similar to chimpanzees (Cold & McGrath, 1999). It is a very small organ, certainly not larger than a fingertip, but the quoted figure of 8000 nerve endings is not inconceivable. We can, however, firmly dispute the claim that it has more nerve endings than the penis! They are thought to be more dense.

The exact nature and distribution of nerve endings in the foreskin has not been investigated since Bazett et al made some secondary counts in the 1920s, and they made a number of assumptions with mistaken identities of type. So we have no real facts to go on, this and the axon mapping of the prepuce and glans being largely unknown.

Until someone repeats the excellent type of study that Halata & Munger did on the glans in 1986, we can only make estimates based upon observational and physiological (University of Washington in the1980s) studies.

I hope this cast a little more light on the dilemma with the hope that my maths is not awry.

Best wishes,

Ken.

Note that the 20,000 number is also called into question here, and one of the persons copied is “Marilyn”, presumably Marilyn Milos, founder of NOCIRC. So, as early as 2008, the message being circulated amongst intactivists was that the number 20,000 was suspect, and 10,000 was wrong, although at this stage they thought the numbers were too low. To clarify I emailed Prof. McGrath himself in 2013. He kindly replied (5 July) and this time had apparently changed his mind and considered that the 10,000 estimate was an order of magnitude too high, and seemed rather exasperated that it was still circulating:

“As to your question: guilty as charged!

No one since about 1923 has published a count of neural receptors in the human penis. At a conference (1998 in Oxford I think) a group asked me to make an estimate of the number of nerve endings in the prepuce. I did a quick back-of-the-envelope guesstimate based on a fingertip and arrived at an orders of magnitude figure of >1000<10000. Like the claimed proportion of men protected from HIV by circumcision, this figure quickly inflated, first to >10,000 and then to >20,000; neither of these is anywhere near the truth, because they are an order of magnitude too high.

In spite of writing it all down last year for a major discussion list, this problem keeps resurfacing. And I have revisited the calculation to put it into a book that a co-author and I have nearly finished. A fortnight ago, a colleague of Wayne and Marilyn asked me to restate the argument to provide rebuttal of the 20,000 figure. So I intend to bring the two slightly different approaches I have used together in response. It would be a pleasure to include you in the distribution of that message.”

Confusingly, here he says his original estimate was “>1000<10000” which is ten times lower than in his 2008 email. But he then states that it inflated to >10,000 so, presumably, he did intend the lower values. I was not included in any subsequent discussions on this topic and, not being privy to whatever the professor wrote for in-house discussions, or an unnamed, unpublished book, cannot say what led him to change his mind. But, to his credit, he did.

The problems are rather obvious. His original calculation based on fingertips makes reference to the distribution of nerve endings in relation to the ridges of fingerprints. This is clearly inappropriate for foreskins (foreskin prints?) And since his 2008 email a study was published which actually measured the density of Meissner’s corpuscles in eight different regions, including fingertips and foreskins, and found that fingertips have the highest concentration, and the foreskin the lowest (Bhat et al., 2008). So, again, it is inappropriate to extrapolate from one to the other. McGrath also uses a large estimate for foreskin size (see below). There have been several studies from China (in Chinese, but summarised by Cox et al., 2015) showing that not all men have Meissner’s corpuscles in their foreskins, and for those that do, they mostly disappear by middle age. Furthermore, since Meissner’s corpuscles are not responsible for erogenous sensation the intactivists’ fascination with them is misplaced.

Having disposed of 10,000, we can turn now to 20,000. Unlike 10,000, this one has a printed source, though not a credible scientific one. It originated in an article that is still influential amongst intactivists to this day, by the late osteopath Paul Fleiss, published in “Mothering: the magazine of natural family living” (Fleiss, 1997). This is a popular, but emphatically not scientific, magazine with a history of promoting fringe and pseudoscientific views, such as anti-vaccination ideas, and HIV/AIDS denialism. Indeed Fleiss himself was an HIV/AIDS denier, and paediatrician to the infamous denier the late Christine Maggiore whose young daughter Eliza died of an AIDS-related illness after Fleiss failed to have the girl tested for HIV, an omission that led to him losing a malpractice suit and being ordered to undergo retraining. For more on this intactivist, quack, and felon, see London (2014).

In his article Fleiss asserts, “circumcision robs a male of … more than 20,000 nerve endings” and cites as his source an obscure paper (Bazett et al., 1932). Problem is Bazett et al. do not say there are 20,000 nerve endings in the foreskin. In fact the number 20,000 does not appear at all anywhere in their paper, so Fleiss has misrepresented Bazett et al. or, to be blunt, he lied (but then he was, after all, a convicted tax fraudster).

To arrive at 20,000 from Bazett et al., Fleiss had to engage in a combination of misrepresentation, and exaggeration. Bazett et al. took a single square centimetre from a single foreskin and endeavoured to count all nerve endings of all types in that one square centimetre. They counted 212, of which only two were the fine-touch receptors that intactivists harp on about, and none were genital corpuscles, the ones that most texts attribute erogenous sensation to.

So they had a sample size of 1, and there was no comparison with any other area of skin to provide a control. Thus we have no idea how representative it is, either between individuals, or across the rest of the body. They do not state where on the foreskin it came from, which matters as nerve ending density may vary from one part of the foreskin to another (there are more nerve endings towards the tip, the so-called “ridged band”, for example). And they do not state the age of the donor, which matters as nerve ending density may change with age. Furthermore, to arrive at 20,000 one has to multiply by 94.3. But 94.3 square centimetres is a huge foreskin, even if the areas of both inner and outer surfaces are added together. In fact it is right up near the top end of the measured range: 7 to 99.8 cm2, the average being about 38.5 cm2 (Kigozi et al., 2009), and this is for both surfaces combined (as confirmed in a personal communication with Dr Kigozi).

None of this mattered for the purposes of Bazett et al.’s study, but Fleiss’ figure of 20,000 is nonsense, being based on a sample size of 1, a bunch of uncertainties, and then inflated to suit his agenda. And, if the original donor was an infant, the number could be wrong by an order of magnitude!

In due course both these numbers got on to the Internet, went viral, and began doing what Internet memes do, and evolved, creating the hybrids and variants that circulate today. They were joined in 2009 by a newcomer …. 70,000 nerve endings! This one can be traced to an Internet article (not in the scientific literature, of course!) by NOCIRC, but which has since disappeared, making it impossible to determine by what process of speculation and exaggeration this meme was arrived at, although 70,000 is mentioned in Prof. McGrath’s email of 2008. Given its dubious origin, and the baseless nature of its smaller forebears, it can be confidently dismissed as just more intactivist garbage.

Not content with 70,000, an intactivist inflated the number to “millions of extra nerve endings” in an article full of the usual Internet myths, speculations and bogus claims (Tasca, 2012). How big can this number get?

As a postscript, no less of a figure than intactivism’s grand matriarch Marilyn Milos has peddled this myth. In one of her submissions to the CDC, when it engaged in a public consultation on circumcision, she asserted that the foreskin, “Contains 20,000-70,000 specialized, erogenous nerves” (Milos, 2015). Referring back to Prof. McGrath’s email of 2007, we see a “Marilyn” copied in there, and mentioned again in the 2013 one. If this is the same Marilyn then one wonders why, knowing that such numbers are dubious, if not downright bogus, she decided to cite them regardless. But then, that’s intactivists for you!

References:
Bazett, H.C., McGlone, B., Williams, R.D., Lufkin, H.M. (1932) Depth, distribution and probable identification in the prepuce of sensory end-organs concerned in sensations of temperature and touch; thermometric conductivity. Archives of Neurology and Psychiatry, 27(3), 489-517. http://www.cirp.org/library/anatomy/bazett/ (abstract & conclusions only).

Bhat, G.M., Bhat, M.A., Kour, K., Shah, B.A. (2008) Density and structural variations of Meissner’s corpuscle at different sites in human glabrous skin. J. Anat. Soc. India, 57(1), 30-3. http://medind.nic.in/jae/t08/i1/jaet08i1p30.pdf

Cox, G., Krieger, J.N., Morris, B.J. (2015) Histological correlates of penile sexual sensation: does circumcision make a difference? Sexual Medicine, 3(2), 76-85. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4498824/

Fleiss, P.M. (1997) The case against circumcision. Mothering, Winter, 36-45. http://www.cirp.org/news/Mothering1997// 

Kigozi, G., Wawer, M., Ssettuba, A., Kagaayi, J., Nalugoda, F., Watya, S., Mangen, F.W., Kiwanuka, N., Bacon, M.C., Lutalo, T., Serwadda, D., Gray, R.H. (2009) Foreskin surface area and HIV acquisition in Rakai, Uganda (size matters). AIDS, 23(16), 2209-13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3125976/

London, W.M. (2014) Medical renegade Paul M. Fleiss dead at 80. Online: http://www.skepticink.com/health/2014/08/12/medical-renegade-paul-m-fleiss-m-d-dead-80/

Milos, M. (2015) Submission to the CDC. Available on-line: https://www.regulations.gov/document?D=CDC-2014-0012-2326

Tasca, E. (2012) Snip the snip. Free Inquiry, 32(2), 53-6. https://secularhumanism.org/2012/02/cont_tasca_32_2/ (subscribers only).
(See letters in the subsequent issue for rebuttals).

The “15 square inches” myth

By Stephen Moreton PhD

December 2016

The following quote is from http://www.circumstitions.com/completeman/ the website of New Zealand intactivist, and retired broadcaster, Hugh Young.

“The average adult foreskin consists of 1½ inches of outer skin, 1½ inches of inner mucosal lining — totaling a length of 3 inches — and is 5 inches in circumference when erect. This amounts to a surface area of 15 square inches, or a surface area equivalent to that of a 3″ by 5″ inch index card!”

And, like so much of the content of his site, it is nonsense. But he is not alone in peddling this myth, it is everywhere in intactivist materials. It is even the name of a website: www.15square.org.uk

As Google and PubMed searches will show, whilst it permeates the internet, it is absent from the scientific literature. As with the “20,000 nerves” myth it is just another intactivist invention. And one that is easy to refute by reading the published research on the topic of foreskin surface area. This will not take long as there are only two papers that measured foreskin surface area.

Werker et al. (1998) took foreskins from 8 cadavers (age of subjects not stated), folded them out and measured the combined inner and outer surface area. They ranged from 18.1 to 67.5 square centimetres (2.8 to 10.5 square inches), average 46.7 cm2 (7.2 square inches).

Kigozi et al. (2009) had a much larger sample size: 965 Ugandan men aged 15 to 49 who volunteered to be circumcised as part of the African anti-HIV program. Although not expressly stated in the study, the surface area they measured was for the folded out foreskin (i.e. inner and outer surface combined), as was confirmed in an email reply to me from the lead author (Dr Kigozi).

The variation in size observed by Dr Kigozi’s team was startling. Measured foreskin surface areas ranged from a mere 7 cm2 (1.1 square inches) to a whopping 99.8 cm2 (15.5 square inches). This is a full order of magnitude. The average was around 38.5 cm2 (6.0 square inches). A few youngsters may account for the smallest foreskins, but the averages across age groups were not much different (35.0 cm2 or 5.4 inch2 for 15–24 year olds; 38.5 cm2 for 25–29 year olds; 38.4 cm2 for 30–49 year olds). A precise breakdown of foreskin size distribution is not given, but 25 % of men had foreskins > 45.6 cm2 (7.1 inch2), 26.1 % < 26.3 cm2 (4.1 inch2), and the remainder in between. The average for the top 25 % of men was 57.6 cm2 (8.9 inch2). Still far short of 15 so, even in these presumably well hung gentlemen, the giant with a 15.5 square inch foreskin is far ahead of the rest. Table 1 in the study tells us that in this top 25 %, a quarter in turn had foreskins > 61.8 cm2 (9.6 inch2), so 60 men could top 9.6 inch2 out of 965, i.e. 6.2 %. In short, out of nearly a thousand men, probably only a handful, maybe even just one or two, could boast a monster prepuce of 15 square inches (96.8 cm2). Since 15 square inches is the figure used by intactivists, for years they have been taking the most extreme value and pretending it is typical.

Related to this exaggerated claim is the assertion that circumcision removes:

“roughly 50% (and sometimes more) of the mobile skin system of the penis.”

This is addressed in detail here: http://circfacts.org/function-sensation/#sens12 .  In any case, as many a circumcised teenage boy will know, there typically remains ample mobility in the shaft skin for all the fun he could want. It is just another of those dubious numbers that intactivists pass off as fact.

Finally, two further observations can be made on the Kigozi study. Firstly, the key finding was that men with larger foreskins were more vulnerable to HIV infection from heterosexual intercourse. So having a big foreskin is not necessarily a good thing. And secondly, as remarked above, foreskins are extremely variable. Much more so than the variation in, say, penis size (about 97 % of men muster 9 to 17 cm erect (Veale et al. 2015)). This is not consistent with the prepuce being an important structure. As Darwin (1859) noted:

“An organ, when rendered useless, may well be variable, for its variations cannot be checked by natural selection.”

References
Darwin, C. (1859) On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. John Murray, London. See chapter 13.  http://darwin-online.org.uk/Variorum/1860/1860-455-c-1861.html 

Kigozi, G., Maria Wawer, M., Ssettuba, A., Kagaayi, J., Nalugoda, F., Watya, S., Mangen, F.W., Kiwanuka, N., Bacon, M.C., Lutalo, T., Serwadda, D., Ronald H. Gray, R.H. (2009) Foreskin surface area and HIV acquisition in Rakai, Uganda (size matters). AIDS, 23(16), 2209-13.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3125976/

Veale, D., Miles, S., Bramley, S., Muir, G., Hodsoll, J. (2015) Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15,521 men. BJU Int., 115(6), 978-86.  https://onlinelibrary.wiley.com/doi/full/10.1111/bju.13010

Werker, P.M.N., Terng, A.S.C., Kon, M. (1998) The prepuce free flap: dissection feasibility study and clinical application of a super-thin new flap. Plast Reconstr Surg., 102(4):1075-82.  https://www.ncbi.nlm.nih.gov/pubmed/9734426 (abstract only).

Keratinization

By Stephen Moreton, PhD

November 2016

One of the most popular of the myths intactivists peddle is that the glans of the circumcised penis becomes keratinized (thickened, hardened, or cornified) over time. This, in turn, is supposed to lead to a loss of sensation, according to the intactivist narrative. A quick internet search will show that this myth is everywhere, sometimes accompanied by cherry-picked, and possibly Photoshopped, pictures of a shiny non-circumcised glans juxtaposed against a dried out wrinkly circumcised one. In fact the myth predates the Internet, even turning up in textbooks, but without any scientific evidence to support it.

The glans of the non-circumcised member is certainly moist, and that of the circumcised one dry, but dry is not the same as keratinized. All external skin is dry (at least when not washing, swimming, etc.) but this is a separate thing from keratinization, which refers to the build-up of layers of dead skin cells, composed of a protein called keratin. This process, also called cornification, results in the skin having a tough protective outer layer.

The idea spread by intactivists is that years of exposure, and rubbing against underwear, results in a thickening of this keratinized, or cornified, layer on the glans, and consequently a loss of sensation in this important part of the penis. An analogy may be the toughening of the skin on the hands of manual workers.

So what is the evidence? In short there isn’t any … only mere anecdotes. One cannot tell how keratinized skin is just by looking, a point made by Dinh & Hope (2010) in relation to the inner versus the outer foreskin. Appearance is misleading, and further confused by the moist vs. dry contrast.

The only way to tell to what extent skin is keratinized is to take actual samples of the skin, section them, stain them for keratin, and measure them down a microscope. And, to date (November 2016), only one study has attempted something like this. Using cadavers Szabo & Short (2000) took skin samples from the glans of 7 circumcised, and 6 non-circumcised men, examined them for keratin, and found no difference.

Frustratingly, they give no further details, such as details of the methodology used, or the actual measurements obtained, but this remains the only attempt to actually compare the two, and they found no difference.

In their study of the glans, Halata & Munger (1986) observed that the rete ridges (downward protrusions of the epithelium) were fewer and shorter in non-circumcised males, but give no actual measurements. They reported no differences in the intervening epithelium. Their sample size was even smaller: 3 circumcised (ages 14, 15 & 69), and 4 not circumcised (ages 22 to 33). With such a small sample size, and the possibility of confounding (rete ridges change with age) it is not possible to draw firm conclusions about the effect of circumcision on glans skin from that study.

So the only scientific data we have, although based on small sample sizes, points away from the keratinization claim. The late pathologist John Taylor, an opponent of circumcision, clearly had doubts about keratinization, describing it as, “Probably not to any significant extent” (http://research.cirp.org/faq1.html).

Given that it would be relatively straightforward to lay this common claim to rest once and for all, by simply measuring a reasonable number of samples and publishing the results, it is surprising that this has not been done. But, until it is, the claim is not based on solid evidence, what scant evidence there is suggests it does not occur, and it is high time intactivists stopped making this claim.

References:
Dinh, M.H. & Hope, T.J. (2010) Keratinization of the adult male foreskin and implications for male circumcision, reply. AIDS, 24, 1381-2. https://insights.ovid.com/pubmed?pmid=20559044 (behind paywall).

Halata, Z. & Munger, B.L. (1986) The neuroanatomical basis for the protopathic sensibility of the human glans penis. Brain Research, 371, 205-30. https://www.ncbi.nlm.nih.gov/pubmed/3697758 (abstract only).

Szabo, R. & Short, R.V. (2000) How does circumcision protect against HIV infection? British Medical Journal, 320, 1592-4. https://www.bmj.com/content/320/7249/1592.full (abstract only).

Gliding along

By Stephen Moreton PhD

December 2016

According to intactivists:

“The foreskin is the only moving part of the penis. During any sexual activity, the foreskin and glans work in unison; their mutual interaction creates a complete sexual response. In heterosexual intercourse, the non-abrasive gliding of the penis in and out of itself within the vagina facilitates smooth and pleasurable intercourse for both partners. Without this gliding action, the corona of the circumcised penis can function as a one-way valve, dragging vaginal lubricants out into the drying air and making artificial lubricants essential for non-painful intercourse.” (Source: http://www.noharmm.org/advantage.htm).

A central tenet of the intactivist mythology of the foreskin is the doctrine of the gliding action. Some even go so far as to call it a “function”, but this is confusing function with property. Extravagant claims are made about the wonders of foreskins that glide back and forth during intercourse. Marvels attributed to this include ease of penetration, stimulation of nerves, enhancing pleasure for both participants, and even a means of preventing vaginal lubricant being drawn out. So what are the facts?

As many a non-circumcised teenage boy will know, except in cases of phimosis (tight foreskin), the foreskin does indeed glide up and down, allowing mobility of the shaft skin, and allowing the glans to be bared or covered in turn. This is not in dispute. But is it as important as claimed?

As is usual for intactivists’ claims, this one is rich in speculation, but lacking in evidence. And when it comes to specific claims about ease of penetration or enhancing pleasure, for every study the intactivists cite in support there is another they don’t, and which finds no difference. The best studies (two randomized controlled trials, a recent large UK survey, a meta-analysis and two large reviews) consistently show no difference in sexual function or satisfaction between circumcised and non-circumcised males (Kigozi et al., 2008; Krieger et al., 2008; Homfray et al. 2015; Tian et al. 2013; Morris & Krieger 2013; Shabanzadeh, et al., 2016). And these include things like pain on intercourse (related to lubrication and penetration), and pleasure or satisfaction. In one of these (Krieger et al. 2008) men reported that sex was actually better after circumcision.  One small study of 19 women noted some reduction in vaginal lubrication, but it evidently did not matter as there was no overall adverse effect (Cortes-Gonzalez, et al., 2008).  But a much larger study (of 455 women) found overwhelmingly either no difference, or an improvement following their partner’s circumcision (Kigozi, et al., 2009). This last did not specifically address gliding or lubrication, but the benefits reported included ease of insertion, and less pain, which should be associated with these. So we can be confident that gliding does not matter, even though research on gliding itself is non-existent.

As ever the “evidence” offered by intactivists is often anecdotal. Someone might say gliding feels good, or helps them copulate. This fits the intactivist narrative, so “it must be true”. But such accounts can be matched by ones saying the opposite. Here is one from a lady who found that gliding was anything but good for her and her partner:

“My b/f is “uncut”; his foreskin fully covers his penis when flaccid and mostly covers it when erect. He is a very energetic sex partner and is a decent size, at least average if not more. My problem is this: when we are having intercourse, much of the “in and out” consists of the “gliding” I’ve read about – his foreskin slides up and down over his penis, which feels like a very thick condom to me, blocking much of the sensation. There’s no friction against my vagina so my pleasure is greatly diminished.  I am plenty wet enough and he is not that sensitive, so it’s good for him to feel his uncovered penis inside me (so those two lines of thought regarding how great “gliding” is are inapplicable to us). We have been together long enough that we do not use condoms, so that is not a solution. I’m hoping to find a way to retract his foreskin down against the bottom half of his penis (towards his body) so that it stays put and does not keep sliding up to cover most of the top half during intercourse.
It’s very frustrating because other than this, our physical relationship is wonderful. I just miss so much of the physical sensation due to his foreskin gliding rather than feeling the friction of his penis inside me.”

(Source: http://www.steadyhealth.com/topics/foreskin-retraction-during-intercourse-for-greater-sensitivity-for-the-woman )

It is not even known how many men actually experience gliding during coitus. Some men do report their foreskins gliding back and forth during sex, but others have short foreskins that retract and end up as a wrinkle behind the glans upon erection. There their foreskin remains, doing little until proceedings have completed, whereupon it returns to its original forward position in the flaccid state. Those men are not experiencing gliding. Do they complain? We don’t even know how many men fall into each camp, or lie somewhere in the middle.

As for those whose foreskins do glide back and forth through intercourse, if so then they are, in effect, having sex with their foreskins, rather than the vagina, as in the account above. Where is the research indicating what they think of it? How many enjoy it? How many don’t? What do their partners think of it? Would the greater stimulation experienced by a bare glans compensate for the absence of gliding in a circumcised male? What would a condom do to it?

Until these basic questions are answered, the supposed wonders of gliding should be treated as nothing more than baseless speculation. Given that the glans is the most erogenous part of the penis (Cox et al., 2015), and gliding enables it to be bared for intercourse, it seems likely that the real reason for gliding is simply a means of getting the foreskin out of the way in preparation for action, and returning it afterwards when done.

References
Cortés-González, J.R., Arratia-Maqueo, J.A., Gómez-Guerra, L.S. (2008) [Does circumcision have an effect on female’s perception of sexual satisfaction?] Rev. Invest. Clin., 60(3), 227-30.  (In Spanish). https://www.ncbi.nlm.nih.gov/pubmed/18807735 (English abstract only).

Cox, G., Krieger, J.N., Morris, B.J. (2015) Histological correlates of penile sexual sensation: does circumcision make a difference? Sex. Med., 3(2), 76-85. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4498824/

Homfray, V., Tanton, C., Mitchell, K.R., Miller, R.F., Field, N., Macdowall, W., Wellings, K., Sonnenberg, P., Johnson, A.M., Mercer, C.H. (2015) Examining the association between male circumcision and sexual function: evidence from a British probability survey, AIDS, 29(11), 1411-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4502984/

Kigozi, G., Watya, S., Polis, C.B., Buwembo, D., Kiggundu, V., Wawer, M.J., Serwadda, D., Nalugoda, F., Kiwanuka, N., Bacon, M.C., Ssempijja, V., Makumbi, F., Gray, R.H. (2008) The effect of male circumcision on sexual satisfaction and function, results from a randomized trial of male circumcision for human immunodeficiency virus prevention, Rakai, Uganda. BJU Int., 101, 65-70. https://www.ncbi.nlm.nih.gov/pubmed/18086100

Kigozi, G., Lukabwe, I., Kagaayi, J., Wawer, M.J., Nantume, B., Kigozi, G., Nalugoda, F., Kiwanuka, N., Wabwire-Mangen, F., Serwadda, D., Ridzon, R., Buwembo, D., Nabukenya, D., Watya, S., Lutalo, T., Nkale, J., Gray, R.H. (2009) Sexual satisfaction of women partners of circumcised men in a randomized controlled trial of male circumcision in Rakai, Uganda. BJU Int., 104, 1698-1701. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2009.08683.x

Krieger, J.N., Mehta, S.D., Bailey, R.C., Agot, K., Ndinya-Achola, J.O., Parker, C., Moses, S. (2008) Adult male circumcision: effects on sexual function and sexual satisfaction in Kisumu, Kenya. J. Sex. Med., 5(11), 2610-22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042320/

Morris, B.J. & Krieger, J.N. (2013) Does male circumcision affect sexual function, sensitivity, or satisfaction?—A systematic review. J. Sex. Med., 10(11), 2644-57. https://www.ncbi.nlm.nih.gov/pubmed/23937309 (abstract only).

Shabanzadeh, D.M., Düring, S., Frimodt-Møller, C. (2016) Male circumcision does not result in inferior perceived male sexual function – a systematic review. Danish Medical Journal, 63(7), 1-9. http://ugeskriftet.dk/dmj/male-circumcision-does-not-result-inferior-perceived-male-sexual-function-systematic-review

Tian, Y., Liu, W., Wang, J-L., Wazir, R., Yue, X, Wang, K-J. (2013) Effects of circumcision on male sexual functions: a systematic review and meta-analysis. Asian J Andrology, 15, 662-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3881635/

The so-called “Lost list”

For years intactivists have bandied around a list of “functions” and marvels supposedly lost to circumcision.  We could debunk it ourselves but, happily, have been beaten to it by a U.K. based skeptic Jake Waskett.  For years Jake was a thorn in the side of intactivists, politely and eloquently exposing their pseudoscience and make-believe.  Tired of the abuse this attracted, and time it consumed, he retired from the debate in 2012.  But his blog, although now inactive, lives on.  However, as there is a risk it may one day disappear we have copied here his excellent debunking of the “Lost list”.  Familiar lies about nerve endings and foreskin size are swiftly dispatched, along with other speculations passed off as fact, and misrepresentations of the scientific literature.  We have inserted a few of our own editorial comments in bold. The original intactivists’ text is in red, Jake’s comments in italics. For the original, see here: http://circumcisionnews.blogspot.co.uk/2011/07/so-called-lost-list.html.

The so-called “lost list”  by Jake Waskett, posted on his blog on Tuesday 12 July 2011

Although less prominent these days, I still find that people occasionally cite the “lost list”, seemingly unaware of its inaccuracies. For those unfamiliar with it, this is a list of structures or functions supposedly lost through circumcision. A number of different versions can be found on the Internet, but they’re very similar. The text below is taken from NORM-UK.  My comments are in italics.

The Foreskin which comprises up to 50% (sometimes more) of the mobile skin system of the penis. If unfolded and spread out flat the average adult foreskin would measure about 15 square inches (the size of a 3×5 inch index card).

This is a gross exaggeration. First, one study has actually measured the surface area of the adult foreskin; it found an average surface area of 36.8 square centimetres (that’s 5.7 square inches). (I previously stated that this was the only study. I was mistaken. A second study, with a small sample size, does exist. It reported an average surface area of 46.7 square centimetres, or 7.2 square inches.) Second, as I recently showed in my critique of Barefoot Intactivist’s propaganda, it is reasonable to estimate that the foreskin constitutes 14% of the penile skin system. Using the surface area figure from Werker et al., that’s 18% — still less than half of the extraordinary 50% figure.
See here for our detailed debunking of intactivists’ claims about foreskin size.  And here for the 50% claim.

This highly specialized tissue normally covers the glans and protects it from abrasion, drying, callusing (also called keratinization), and contaminants of all kinds. The effect of glans keratinisation has never been studied.

This sentence is dubious in many ways. The most obvious is the statement that the foreskin protects the glans from keratinisation — the only study in the literature to have examined keratinisation by circumcision status found no differences between the level of keratinisation of the circumcised and uncircumcised glans. Less obvious, but still troubling, is the implication that the circumcised glans is susceptible to abrasion or “contaminants”. No evidence is cited in support.

See here for our detailed debunking of intactivists’ claims about keratinisation.
[1. M. M. Lander, “The Human Prepuce,” in G. C. Denniston and M. F. Milos, eds., Sexual Mutilations: A Human Tragedy (New York: Plenum Press, 1997), 79-81. 2. M. Davenport, “Problems with the Penis and Prepuce: Natural History of the Foreskin,” British Medical Journal 312 (1996): 299-301.]

Note that only two sources are cited. One (Davenport) is peer-reviewed but does not support any of the claims attributed to it. The other (Lander) is a non-peer-reviewed paper presented at an anti-circumcision conference, which doesn’t inspire confidence.

The Frenar Ridged Band, the primary erogenous zone of the male body.

When I see a claim like this, I immediately wonder: who established this, and what was the study methodology? The cited source (Taylor, see below) established nothing of the sort. While a small number of studies have investigated sensitivity to non-sexual stimulus, only one study, to my knowledge, has investigated the relative degree of sexual pleasure produced by various parts of the anatomy. That study (which was unfortunately limited by the small number of uncircumcised men) found that the foreskin actually produces the least sexual pleasure of any part of the penis.

Loss of this delicate belt of densely innervated, sexually responsive tissue reduces the fullness and intensity of sexual response.
[Taylor, J. R. et al., “The Prepuce: Specialized Mucosa of the Penis and Its Loss to Circumcision,” British Journal of Urology 77 (1996): 291-295.]

Note that the cited source says nothing of the sort! Its authors merely “postulate” that the “ridged band” is sensory tissue. They don’t attempt to prove it, nor do they evaluate the effects of its removal on the “fullness and intensity” of sexual response.

The Foreskin’s ‘Gliding Action’ – the hallmark mechanical feature of the normal natural, intact penis. This non-abrasive gliding of the penis in and out of itself within the vagina facilitates smooth, comfortable, pleasurable intercourse for both partners. Without this gliding action, the corona of the circumcised penis can function as a oneway valve, scraping vaginal lubricants out into the drying air and making artificial lubricants essential for pleasurable intercourse.
[P. M. Fleiss, MD, MPH, “The Case Against Circumcision,” Mothering: The Magazine of Natural Family Living (Winter 1997): 36-45.]

Note that the only source cited for this claim is an opinion piece published in a magazine. It’s an interesting hypothesis, but little or no credible evidence supports it.
See here for our detailed debunking of intactivists’ claims about gliding.

Nerve Endings transmit Sensations to the Brain – Fewer Nerve Endings means Fewer Sensations

This simplistic model is faulty because the presence of nerve endings do not create sensations by themselves. Likely as not, your genitals are not buzzing with sensations as you read this, because they’re not being stimulated. This means that the method and degree of stimulation is as important as the number of nerve endings. Put simply, a smaller number of nerve endings can produce just as much stimulation as a larger number, if stimulated more effectively. And this is effectively what circumcision achieves, by exposing the glans (especially the sensitive corona) to direct stimulation during intercourse, sensation is increased, compensating for the loss of sensation from the foreskin itself.

Circumcision removes the most important sensory component of the foreskin – thousands of coiled fine-touch receptors called Meissner’s corpuscles.

Most important? Who established this, and what was the study methodology?

Also lost are branches of the dorsal nerve, and between 10,000 and 20,000 specialized erotogenic nerve endings of several types.

What is the source for this number? Neither of the two cited sources support it. In fact, having researched this in some depth, I feel quite confident in stating that no study has ever counted the number of nerve endings in the foreskin.
See here for our detailed debunking of the 10,000 and 20,000 nerves myths.

Together these detect subtle changes in motion and temperature, as well as fine gradations in texture.
[1. R. K. Winkelmann, “The Erogenous Zones: Their Nerve Supply and Its Significance,” Proceedings of the Staff Meetings of the Mayo Clinic 34 (1959): 39-47. 2. R. K. Winkelmann, “The Cutaneous Innervation of Human Newborn Prepuce,” Journal of Investigative Dermatology 26 (1956): 53-67.]

Again, the sources fail to support the claims attributed to them.

The Frenulum: The highly erogenous V-shaped web-like tethering structure on the underside of the glans; frequently amputated along with the foreskin, or severed, either of which destroys its function and potential for pleasure.
[1. Cold, C, Taylor, J, “The Prepuce,” BJU International 83, Suppl. 1, (1999): 34-44. 2. Kaplan, G.W., “Complications of Circumcision,” Urologic Clinics of North America 10, 1983.]

Neither of the cited sources actually supports these claims. This isn’t terribly surprising because a) the frenulum’s potential for pleasure is speculative, and b) the function of the frenulum, such as it is, is to hold the foreskin in place over the glans. Without a foreskin, then, it has no function.

Muscle Sheath: Circumcision removes approximately half of the temperature-sensitive smooth muscle sheath which lies between the outer layer of skin and the corpus cavernosa. This is called the dartos fascia.
[Netter, F.H., “Atlas of Human Anatomy,” Second Edition (Novartis, 1997): Plates 234, 329, 338, 354, 355.]

“Approximately half” is of course an exaggeration, but it is true that the foreskin does contain this layer.

The Immunological Defense System of the soft mucosa. This produces both plasma cells that secrete immunoglobulin antibodies and antibacterial and antiviral proteins such as the pathogen-killing enzyme lysozyme.
[1. A. Ahmed and A. W. Jones, “Apocrine Cystadenoma: A Report of Two Cases Occurring on the Prepuce,” British Journal of Dermatology 81 (1969): 899-901. 2. P. J. Flower et al., “An Immunopathologic Study of the Bovine Prepuce,” Veterinary Pathology 20 (1983):189-202.]

The cited sources utterly fail to support these claims. The second is not even a study of the human prepuce, but rather that of the cow! While the foreskin doubtless contains the immunological functions of any skin, no special mechanisms are known.

Lymphatic Vessels: the loss of which reduces the lymph flow within that part of the body’s immune system.
[Netter, F.H., “Atlas of Human Anatomy,” Second Edition (Novartis, 1997): plate 379.]

This is really scraping the bottom of the barrel, but yes, removing skin does remove the lymph vessels within it.

Oestrogen Receptors The presence of estrogen receptors within the foreskin has only recently been discovered. Their purpose is not yet understood and needs further study.
[R. Hausmann et al., “The Forensic Value of the Immunohistochemical Detection of Oestrogen Receptors in Vaginal Epithelium,” International Journal of Legal Medicine 109 (1996): 10-30.]

If confirmed, for that matter.

The Body is Well Designed – Altering it Surgically can only Disrupt it’s Natural Function

This is more a statement of faith than a serious claim, but we can transform it into a scientifically testable hypothesis: surgical alteration of the body cannot produce positive effects. It seems almost trivial to show that it is false.

The Apocrine Glands [sweat glands] of the inner foreskin, which produce pheremones -nature’s powerful, silent, invisible behavioural signals to potential sexual partners. The effect of their absence on human sexuality has never been studied.
[A. Ahmed and A. W. Jones, “Apocrine Cystadenoma: A Report of Two Cases Occurring on the Prepuce,” British Journal of Dermatology 81 (1969): 899-901.]

A serious problem with this claim is that apocrine glands are absent in the inner foreskin. Amusingly, one of the sources cited above (Taylor et al) says this: “the mucosal surface of the prepuce is completely free of lanugo hair follicles, sweat and sebaceous glands”. Similarly, Parkash et al report: “Multiple small pieces were taken from the inner lining of the circumcised prepuce […] A special search was made for glandular tissue. No such tissue was found in the material”.

Sebaceous Glands which lubricate and moisturise the foreskin and glans, normally a protected and internal organ-like the tongue or vagina. Not all men have sebaceous glands on their inner foreskin.
[A. B. Hyman and M. H. Brownstein, “Tyson’s Glands: Ectopic Sebaceous Glands and Papillomatosis Penis,” Archives of Dermatology 99 (1969): 31-37.]

In fact, according to the studies cited above, no men have sebaceous glands on their inner foreskin.

Langerhans Cells Specialised epithelial Langerhans cells, a first line component of the body’s immune system in a whole penis.
[G. N. Weiss et al., “The Distribution and Density of Langerhans Cells in the Human Prepuce: Site of a Diminished Immune Response?” Israel Journal of Medical Sciences 29 (1993): 42-43.]

The cited source actually states the opposite: that the foreskin is deficient in Langerhans cells.

Colouration: The natural coloration of the glans and inner foreskin (usually hidden and only visible to others when sexually aroused) is considerably more intense than the permanently exposed and keratinized coloration of a circumcised penis. The socio-biological function of this visual stimulus has never been studied.

Ignoring the keratinisation error, this seems to be rather desperate. The appearance of the penis is changed, so this is a loss?

Some of the penis length and circumference because its double-layered wrapping of loose and usually overhanging foreskin is now missing, making the circumcised penis truncated and thinner than it would have been if left intact. An Australian survey in 1995 showed circumcised men to have erect penises an average of 8mm shorter than intact men.
[1. R. D. Talarico and J. E. Jasaitis, “Concealed Penis: A Complication of Neonatal Circumcision,” Journal of Urology 110 (1973): 732-733. 2. Richters J, Gerofi J, Donovan B. Why do condoms break or slip off in use? An exploratory study. Int J STD AIDS. 1995; 6(1):11-8. ]

It should be noted that this Australian study is in fact the only study to report such a difference.
The circumcised men in the 1995 study were also older than the non-circumcised ones.  This could be the reason their erections were slightly smaller or weaker (Rivin et al., 2016, Critical evaluation of Adler’s challenge to the CDC’s circumcision recommendations. Int. J. Children’s Rights, 24, 265-303. See p. 275).

Blood Vessels: Several feet of blood vessels, including the frenular artery and branches of the dorsal artery are removed in circumcision. This loss of the rich vascularity interrupts normal flow to the shaft and glans of the penis, damaging the the natural function of the penis and altering its development.
[1. H. C. Bazett et al., “Depth, Distribution and Probable Identification in the Prepuce of Sensory End-Organs Concerned in Sensations of Temperature and Touch; Thermometric Conductivity,” Archives of Neurology and Psychiatry 27 (1932): 489-517.� 2. Netter, F.H., “Atlas of Human Anatomy,” Second Edition (Novartis, 1997): plates 238, 239.]

It is quite likely that several feet are lost, as the human body has an extraordinary number of blood vessels (a typical estimate is that the adult human body contains 100,000 miles of blood vessels). The claimed consequences, however, are unsupported by the references cited.

Dorsal Nerves: The terminal branch of the pudendal nerve connects to the skin of the penis, the prepuce, the corpora cavernosa, and the glans. Destruction of these nerves is a rare but devastating complication of circumcision. If cut during circumcision, the top two-thirds of the penis will be almost completely without sensation.
[1. Agur, A.M.R. ed., “Grant’s Atlas of Anatomy,” Ninth Edition (Williams and Wilkins, 1991): 188-190. 2. Netter, F.H., “Atlas of Human Anatomy,” Second Edition (Novartis, 1997): plate 380, 387.]

One wonders why such extremely rare, albeit possible complications are included, then. To pad out the list, perhaps?

Complications: Every year boys lose their entire penises from circumcision accidents and infection. They are then “sexually reassigned” by castration and “transgender surgery” and expected to live their lives as “females”.
[1. J. P. Gearhart and J. A. Rock, “Total Ablation of the Penis after Circumcision with Electrocautery: A Method of Management and Long-Term Follow up,” Journal of Urology 142 (1989):799-801. 2. M. Diamond and H. K. Sigmundson, “Sex Reassignment at Birth: Long-Term Review and Clinical Implications,” Archives of Pediatrics and Adolescent Medicine 151 (1997): 298-304.]

It may be an exaggeration to claim that this happens “every year”, but cases have been reported, unfortunately.

Death: Every year many boys lose their lives from the complications of circumcision, a fact the billion-dollar-a-year circumcision industry in the U.S. routinely obscures and ignores.
[1. G. W. Kaplan, “Complications of Circumcision,” Urologic Clinics of North America 10 (1983): 543-549. 2. R. S. Thompson, “Routine Circumcision in the Newborn: An Opposing View,” Journal of Family Practice 31 (1990): 189-196.]

Again, death does occur, albeit rarely. However, it would be foolish to consider such deaths in isolation. They should be weighed against deaths attributable to lack of circumcision. That is, if a million boys are circumcised, does this result in more or fewer deaths than if those boys are not circumcised. The evidence indicates that lives are saved.

Emotional Bonding: Circumcision performed during infancy disrupts the bonding process between child and mother. There are indications that the innate sense of trust in intimate human contact is inhibited or lost.

Who established this, and what was the study methodology?
This has already been investigated in relation to breastfeeding.  Circumcision makes no difference: Fergusson et al. (2008) Neonatal circumcision: Effects on breastfeeding and outcomes associated with breastfeeding. J. Paediatrics & Child Health, 44(1-2), 44-9.  Mondzelewski et al. (2016) Timing of circumcision and breastfeeding initiation among newborn boys.  Hospital Paediatrics, 6(11), 653-8.

It can also have significant adverse effects on neurological development. Additionally, an infant’s self-confidence and hardiness is diminished by forcing the newborn victim into a defensive psychological state of “learned helplessness” or “acquired passivity” to cope with the excruciating pain which he can neither fight nor flee.

Who established this, and what was the study methodology? How on Earth would one be able to prove such a thing? It looks suspiciously like an unfalsifiable statement: a product of pseudoscience, not science.
This has been claimed in connection with autism, and soundly rejected by the scientific community.  We hope to write a dedicated rebuttal on this topic in due course.

The trauma of this early pain lowers a circumcised boy’s pain threshold below that of intact boys and girls.
[1. R. Goldman, Circumcision: The Hidden Trauma (Boston: Vanguard Publications, 1997), 139-175. 2. A. Taddio et al., “Effect of Neonatal Circumcision on Pain Responses during Vaccination in Boys,” Lancet 345 (1995): 291-292.]

Neurological Sexual Communication: Although never studied scientifically, contemporary evidence suggests that a penis without its foreskin lacks the capacity for the subtle neurological “cross-communication” that occurs only during contact between mucous membranes and which contributes to the experience of sexual pleasure.

What utter nonsense! How on earth would non-scientific evidence suggest such a thing? This appears to be nothing more than a wild theory, dishonestly presented as something suggested by evidence.

Amputating an infant boy’s multi-functional foreskin is a “low-grade neurological castration” [Immerman], which diminishes the intensity of the entire sexual experience for both the circumcised male and his partner.

So prove it. Should be trivial. Except, of course, that scientific studies of satisfaction, etc., don’t support this claim.


16 functions – 16 speculations

A popular intactivist meme is that the foreskin has 16 functions.  A list usually follows of these purported “functions”, but they range from insignificant to rampant speculation to exercises in barrel-scraping.  Now we could debunk each in turn but, happily, have been beaten to it by the folks at Circumcision Choice.  See https://www.circumcisionchoice.com/single-post/16Functions. Enjoy.

While we are on this theme, just to be fair to intactivists, we have identified a 17th function of the foreskin they ought to include on their list.  Here it is:
http://www.thenorthernecho.co.uk/news/5071173.Prison_visitor_caught_with_drugs_hidden_inside_foreskin

http://www.metro.co.uk/2016/07/28/man-who-hid-7-grams-of-cocaine-under-his-foreskin-jailed-6034163/


The glans becomes less sensitive after circumcision

Like the argument about keratinization the hypothesis that the glans becomes less sensitive after circumcision has been around a long time. It was not originally an intactivist claim, but it is one they have adopted and assiduously cultivated. The argument speculates that after circumcision the surface of the exposed glans dries, rubs against underwear, and becomes keratinized, which leads to a loss of sensation. As a measure of the success of this meme even some so-called “skeptics” who should know better than to uncritically copy popular beliefs without fact-checking them first, have fallen for it. To quote a high-profile English skeptic who manages to get nearly everything wrong in his presentation on circumcision (https://mylespower.co.uk/2013/03/30/the-science-of-circumcision/):

“… the glans becomes thicker through a process called keratinisation. The process desensitises the glans and again, decreases sexual pleasure.”

But since keratinization is itself a myth (http://circfacts.org/function-sensation/#sens3) why should the glans be desensitized? Furthermore, because a reduction in sensation may increase a man’s staying power, not all men would consider it a bad thing anyway. But does it happen?

The short answer is no, nevertheless, intactivists cherry-pick a few weak studies “proving” the contrary. Probably the most popular of these studies is one by Sorrells et al., (2007) in which volunteers had the fine-touch sensitivity of various parts of their genitals tested by application of a filament. The authors concluded, amongst other things, that, “The glans in the circumcised male is less sensitive to fine-touch pressure than the glans of the uncircumcised male”.

However, the study was swiftly shown to be flawed in multiple ways. The authors put their initial results into their Table 2, and then tried to analyse them further using a mixed model, the results of which appeared in their Table 3, and were referred to in their Discussion. But critics (Waskett & Morris, 2007) pointed out that when corrected for multiple comparisons (a basic requirement for statistical analyses involving multiple measurements) the data in their Table 2 were no longer statistically significant. Furthermore, the authors had not compared the same points on the circumcised and non-circumcised penis. When this was done by their critics, no difference was found. And some of the analyses were peculiar. According to the authors, being Hispanic and type of underwear made a significant contribution to penile sensitivity. So Mexican men wearing briefs have different penises to other men!

For details of the multiple problems with this oft-cited paper, funded and conducted by NOCIRC, an intactivist organization, see Waskett & Morris (2007). Attempts by intactivists to defend this “favorite” work of theirs’ have been rebutted (Morris et al., 2017). In fact, one of these attempts is even used on this website as an example of the straw man fallacy (http://circfacts.org/sloppy-logic/#slog32). It should also be noted that the study only looked at fine-touch, but this is not relevant to sexual sensation, making the whole thing a red herring anyway (http://circfacts.org/sloppy-logic/#slog30).

Another study popular with intactivists, and purporting to show a loss of sensation following circumcision, is Bronselaer et al., (2013), conducted in Belgium. As with the previous, it too is flawed. Critics pointed out a series of methodological and statistical problems (Morris et al., 2013). One glaring issue was the way the volunteers were recruited – by advertising. Anyone familiar with intactivist shenanigans will know that they have a habit of flagging, on social media, studies and surveys relating to circumcision, and urging the faithful to participate in order to skew the results (http://circfacts.org/cyber-bullying/#cyber13). Even without this behavior, any such study will likely attract those with an interest, or agenda. As a result the study sample is unlikely to be representative.

This well-known effect is called “selection bias”, or “participant bias”, and is a fundamental weakness of cross-sectional studies of this sort. With care, it may be possible to minimize it, but there is clear evidence that selection bias blighted the Bronselaer study: 22.6 % of their participants were circumcised, but in his reply (Bronselaer, 2013) the lead author conceded that the circumcision rate in Belgium is actually 15 %. Thus there is a clear over-representation of circumcised males in his study. Later critics pointed out, amongst other problems, that 12.1 % of the sample were gay, leaving one wondering just how unrepresentative it actually is (Wang et al., 2013).

So what does the science say about the sensitivity of the circumcised versus non-circumcised penis? Excluding studies in which men were circumcised for medical problems, which tend to have small sample sizes, and give mixed results from which it is difficult to tease out the possible effect of the pathology for which they were circumcised, as of the time of writing (December 2017) here are the studies intactivists don’t tell their audience about:

No difference in penile sensitivity between circumcised and non-circumcised men, as measured by various objective tests:  Bleustein et al., (2005); Bossio et al., (2016); Masters & Johnson, (1966); Payne et al., (2007); Waskett & Morris (2007).

No difference in penile sensitivity between circumcised and non-circumcised men, as self-reported by men circumcised as adults, and thus able to compare before and after: Galukande et al., (2017)* (actually mixed results: 18.4 % reported heightened glans sensitivity, 6.2 % lowered, the remaining 75.4 %, presumably, no change).

Sensation improved after circumcision (self-report by men circumcised as adults): Brito et al., (2017)*; Krieger et al., (2008)*.

No difference, or improvement in penile sensation, following circumcision, indicated by systematic literature reviews: Cox et al., (2015)*; Morris & Krieger, (2013)*; Shabanzadeh et al., (2016)*.

Those marked with an asterisk fall in the upper tiers of the hierarchy of evidence (https://online.manchester.ac.uk/bbcswebdav/orgs/I3075-COMMUNITY-MEDN-1/DO%20NOT%20DELETE%20-%20PEP%20Quality%20and%20Evidence/QE-PEP-HTML5/AN-232E8560-4F14-1254-C272-DE02E63DB32D.html) and so may be regarded as high quality evidence.

The science is clear: circumcision does not lead to desensitization of the glans.

References
Bleustein, C.B., Fogarty, J.D., Eckholdt, H., Arezzo, J.C., Melman, A. (2005) Effect of neonatal circumcision on penile neurologic sensation. Urology, 65(4), 773-7. https://www.sciencedirect.com/science/article/pii/S0090429504013433 (abstract only).

Bossio, J.A., Pukall, C.F., Steele, S.S. (2016) Examining penile sensitivity in neonatally circumcised and intact men using quantitative sensory testing. J. Urol., 195(6), 1848-53. https://www.auajournals.org/doi/full/10.1016/j.juro.2015.12.080

Brito, M.O., Khosla, S., Pananookooln, S., Fleming, P.J., Lerebours, L., Donastorg, Y., Bailey, B.C. (2017) Sexual pleasure and function, coital trauma, and sex behaviors after voluntary medical male circumcision among men in the Dominican Republic. J. Sex. Med., 14(4), 526-4. https://www.ncbi.nlm.nih.gov/pubmed/28258953

Bronselaer, G.A., Schober, J.M., Meyer-Bahlburh, H.F.L., T’Sjoen, G., Vlietinck, R., Hoebeke, P.B. (2013) Male circumcision decreases penile sensitivity as measured in a large cohort. BJU Int., 111(5), 820-7. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2012.11761.x

Bronselaer, G.A. (2013) Reply. BJU Int., 111(5), E270-1. https://onlinelibrary.wiley.com/doi/full/10.1111/bju.12128_10

Cox, G., Krieger, J.N., Morris, B.J. (2015) Histological correlates of penile sexual sensation: Does circumcision make a difference? Sex. Med. 3(2), 76-85. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4498824/

Galukande, M., Nakaggwa, F., Busisa, E., Sekavuga Bbaale, D., Nagaddya, T., Coutinho, A. (2017) Long term post PrePex male circumcision outcomes in an urban population in Uganda: a cohort study. BMC Res. Notes, 10, 522. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5663120/

Krieger, J.N., Mehta, S.D., Bailey, R.C., Agot, K., Ndinya-Achola,J.O., Parker, C., Moses, S. (2008) Adult male circumcision: Effects on sexual function and sexual satisfaction in Kisumu, Kenya. J. Sex. Med., 5(11), 2610-22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042320/

Masters, W.H. and Johnson, V.E. (1966) Human Sexual Response. Boston: Little, Brown & Co., p. 189.

Morris, B.J., Barboza, G., Wamai, R.G., Krieger, J.N. (2017) Expertise and ideology in statistical evaluation of circumcision for protection against HIV infection. World J. AIDS, 7, 179-203.  (See p. 182). https://www.scirp.org/journal/PaperInformation.aspx?PaperID=78405

Morris, B.J., Krieger, J.N. (2013) Does male circumcision affect sexual function, sensitivity or satisfaction? – A systematic review. J. Sex. Med., 10(11), 2644-57. https://www.ncbi.nlm.nih.gov/pubmed/23937309

Morris, B.J., Krieger, J.N., Kigozi, G. (2013) Male circumcision decreases penile sensitivity as measured in a large cohort (Letter). BJU Int., 111(5), E269-70. https://onlinelibrary.wiley.com/doi/full/10.1111/bju.12128_9

Payne, K., Thaler, L., Kukkonen, T., Carrier, S., Binik, Y. (2007) Sensation and sexual arousal in circumcised and uncircumcised men. J. Sex. Med., 4(3), 667-74. https://www.ncbi.nlm.nih.gov/pubmed/17419812

Shabanzadeh, D.M., During, S., Frimodt-Møller, C. (2016) Male circumcision does not result in inferior perceived male sexual function – a systematic review. Danish Med. J., 63(7), 9 pages. http://ugeskriftet.dk/dmj/male-circumcision-does-not-result-inferior-perceived-male-sexual-function-systematic-review

Sorrells, M.J., Snyder, J.L., Reiss, M.D., Eden, C., Milos, M.F. (2007) Fine-touch pressure thresholds in the adult penis. BJU Int., 99(4), 864-9. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2006.06685.x

Wang, K., Tian, Y., Wazir, R. (2013) Male circumcision decreases penile sensitivity as measured in a large cohort (Letter). BJU Int., 112(1), E2. https://onlinelibrary.wiley.com/doi/full/10.1111/bju.12234_4

Waskett, J.H., Morris, B.J. (2007) Fine-touch pressure thresholds in the adult penis (Letter). BJU Int., 99(6), 1551-2. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2007.06970_6.x

Circumcised men are 4.5 times more likely to use an erectile dysfunction drug

The source of this claim is a paper by Dan Bollinger and Robert S. Van Howe (2011). It quickly became popular amongst intactivists and has been eagerly cited by them ever since. Whilst the main focus of their study was on alexithymia, a problematic personality trait they were trying to link to circumcision, they also inquired about erectile dysfunction, and the use of medication, to treat such dysfunction. The authors concluded that circumcised men were more likely to suffer from alexithymia, and also 4.53 times more likely to use an erectile dysfunction drug, the implication being that circumcision causes erectile difficulties. But, as is usual for these two well-known intactivists, their claims do not withstand scrutiny.

An immediate and obvious problem is the way in which the 300 study subjects (236 of them circumcised) were recruited. As pointed out in a critique (Morris & Waskett, 2012) its self-selected sample was recruited through advertisements on two websites with strongly anti-circumcision content. It is hard to imagine a more effective way of ensuring a biased sample, short of advertising specifically for circumcision opponents. Indeed, the “loaded” title of the advertisement, “Male circumcision trauma survey” comes close to doing exactly that. In their reply to the critique, Bollinger & Van Howe (2012) conceded the potential for bias, and that their results are “unconfirmed”.

In short, the study was set-up in such a way so as to ensure that the respondents would include men opposed to circumcision, or disgruntled with their own circumcision. Such individuals are bound to give negative feedback, whilst those with no interest in the subject, or happy with their circumcisions, are much less likely to participate. This is called “selection bias”, or “participant bias”, and is a fundamental weakness of cross-sectional studies such as this. In fact, given the propensity of intactivists to flag such studies on social media (http://circfacts.org/cyber-bullying/#cyber13), it would be unsurprising if some of the participants were there purely to skew the results in favor of the intactivist agenda.

This alone severely compromises the study, but the problems don’t end there. A closer inspection of the data shows that there was no significant difference in occurrence of erectile dysfunction between circumcised and non-circumcised males (Table 3). What differed was the use of erectile dysfunction medication. One cannot conclude from those results that circumcision causes erectile dysfunction. Of course this has not stopped intactivists proclaiming that it does. The authors were more careful in their choice of words, focusing instead on the difference in erectile dysfunction drug use. They gave a nod to a possible alternative explanation – such drug use may relate to the ability to afford it – but did not adequately explore that possibility.

Use of erectile dysfunction drugs can be recreational, and most of the study participants were American. One hardly needs to invoke circumcision to account for recreational drug use in one of the wealthiest and, arguably, most decadent societies on earth. In addition, many studies have found that circumcision is more common amongst people of higher socioeconomic status, and thus more able to afford drugs.

In short, intactivists place too much faith in a single study with a biased sample by biased authors. Indeed, even the authors couch their language in cautious terms: “preliminary” and “unconfirmed”, whilst acknowledging the potential for bias. Science does not move on single studies, let alone ones as weak as this. Science moves on bodies of evidence (https://forthesakeofscience.com/2017/03/10/science-moves-on-bodies-of-evidence/ ).

So, what does the body of evidence say? The great majority of studies fail to find any association between circumcision and erectile problems. To review them all would be tedious so we will restrict ourselves to the very best quality studies (i.e., in the top tiers of the hierarchy of evidence: https://online.manchester.ac.uk/bbcswebdav/orgs/I3075-COMMUNITY-MEDN-1/DO%20NOT%20DELETE%20-%20PEP%20Quality%20and%20Evidence/QE-PEP-HTML5/AN-232E8560-4F14-1254-C272-DE02E63DB32D.html ). Not every study in those top tiers evaluated erectile function, but those that did, from case-control upwards, were:

Case control study (Nordstrom et al., 2017, n >3,000): no difference in erectile function between circumcised and non-circumcised men.

Cohort study (Brito et al., 2017, n = 500): improved erections 58 %, no difference 40 %.

Randomized controlled trial (Kigozi et al., 2008, n = ca. 1,500): no difference.

Randomized controlled trial (Krieger et al., 2008, n = 1,195): no difference.

Systematic review (Morris & Krieger, 2013): no difference.

*Systematic review (Shabanzadeh et al., 2016): no difference.

*Systematic review & meta-analysis (Tian et al., 2013): no difference.

*Systematic review & meta-analysis (Yang et al., 2017): identified one small study (n = 95) of men circumcised for medical reasons in which there was increased erectile difficulty following circumcision (but those men were older and mostly diabetic), and four studies in which erectile difficulties decreased following circumcision; hence, overall, improvement.

Those marked with an asterisk (*) were by workers from non-circumcising cultures, so not likely to be biased in favour of the procedure. Note also the large sample sizes (n) for some of the studies, and the inherently better study designs that exclude selection bias.

The evidence is clear. All the best quality studies find that circumcision has no adverse effect on erectile function.

For details on the alexithymia claim see: http://circfacts.org/medical-benefits/risks-complications/#risk1

References
Bollinger, D., Van Howe, R.S. (2011) Alexithymia and circumcision trauma: A preliminary investigation. Int. J. Men’s Health, 10(2), 184-95. https://pdfs.semanticscholar.org/676d/b908ff4629702b99da6d77739d1300370bd4.pdf

Bollinger, D., Van Howe, R.S. (2012) Preliminary results are preliminary, not “unfounded”: Reply to Morris and Waskett. Int. J. Men’s Health, 11(2), 181-5.

Brito, M.O., Khosla, S., Pananookooln, S., Fleming, P.J., Lerebours, L., Donastorg, Y., Bailey, R.C. (2017) Sexual pleasure and function, coital trauma, and sex behaviors after voluntary medical male circumcision among men in the Dominican Republic. J. Sex. Med., 14(4), 526-34. https://www.ncbi.nlm.nih.gov/pubmed/28258953 (abstract only).

Kigozi, G., Watya, S., Polis, C.B., Buwembo, D., Kiggundu, V., Wawer, M.J., Serwadda, D., Nalugoda, F., Kiwanuka, N., Bacon, M.C., Ssempijja, V., Makumbi, F., Gray, R.H. (2008) The effect of male circumcision on sexual satisfaction and function, results from a randomized trial of male circumcision for human immunodeficiency virus prevention, Rakai, Uganda. BJU Int., 101(1), 65-70. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1464-410X.2007.07369.x

Krieger, J.N., Mehta, S.D., Bailey, R.C., Agot, K., Ndinya-Achola, J.O., Parker, C., Moses, S. (2008) Adult male circumcision: Effects on sexual function and sexual satisfaction in Kisumu, Kenya. J. Sex. Med., 5(11), 2610-22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042320/

Morris, B.J., Waskett, J.H. (2012) Claims that circumcision increases alexithymia and erectile dysfunction are unfounded: A critique of Bollinger and Van Howe’s “Alexithymia and circumcision trauma: A preliminary investigation”. Int. J. Men’s Health, 11(2), 177-81. https://www.thefreelibrary.com/Claims+that+circumcision+increases+alexithymia+and+erectile…-a0305192594

Morris, B.J., Krieger, J.N. (2013) Does male circumcision affect sexual function, sensitivity, or satisfaction?—A systematic review. J. Sex. Med. 10(11), 2644-57. https://www.ncbi.nlm.nih.gov/pubmed/23937309

Nordstrom, P.C., Westercamp, N., Jaoko,W., Okeyo, T., Bailey, R.C. (2017) Medical male circumcision is associated with improvements in pain during intercourse and sexual satisfaction in Kenya. J. Sex. Med., 14(4), 601-12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5388349/

Shabanzadeh, D.M., Düring, S., Frimodt-Møller, C. (2016) Male circumcision does not result in inferior perceived male sexual function – a systematic review. Dan. Med. J., 63(7), A5245. http://ugeskriftet.dk/dmj/male-circumcision-does-not-result-inferior-perceived-male-sexual-function-systematic-review

Tian, Y., Liu, W., Wang, J-Z., Wazir, R., Yue, X., Wang, K-J. (2013) Effects of circumcision on male sexual functions: a systematic review and meta-analysis. Asian J, Androl., 15(5), 662-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3881635/

Yang, Y., Wang, X., Bai, Y., Han, P. (2017) Circumcision does not have effect on premature ejaculation: A systematic review and meta-analysis. Andrologia, ePub ahead of print. Abstract here: https://www.ncbi.nlm.nih.gov/pubmed/28653427

Lubrication and lubricant

Claims relating to lubrication fall into two, overlapping, camps. One is that the foreskin itself has a lubricating effect during intercourse. The other is that circumcised men need artificial lubricant to assist matters, whether during coitus, or masturbation.

Dealing with the first of these first, quite why a foreskin should have this effect is unclear, but it is commonly attributed to the wonderful gliding action. For example, the intactivist website cirp.org which is useful as a free source of articles (at least articles that support the intactivists’ cause), but of little use for anything else, claims (http://www.cirp.org/library/sex_function/):

“The foreskin provides mechanical functions to facilitate intromission and penetration. Several authorities observe that the penis enters the vagina without friction as the foreskin unfolds.4 9 10 11 Taves (2002) reported that excision of the foreskin by circumcision increases the force required to penetrate by ten-fold.51 Shen et al. reported 43.1 percent of men cirumcised [sic] as adults experience difficult penetration.59 After penetration, the foreskin provides a gliding action that greatly reduces friction,4 9 11 15 41 49and vaginal dryness.27 40 50 55”

As with many “intactofacts” this one lacks empirical evidence in support. It is mere speculation, passed off as “fact”. At first glance the quote above seems backed up by an impressive number of references, and few readers would have the time, or inclination, to check each one. If they were to do so they would be disappointed, as the citations do not adequately support the claim: http://circfacts.org/sloppy-logic/#slog23

Also, many men find that their foreskins retract and remain behind the glans during coitus (see: http://circfacts.org/function-sensation/#sens4  ) doing little. How can they benefit from this putative gliding/lubricating effect?

The intactivists offer unsubstantiated opinions, and weak studies of biased samples by biased authors, but they lack hard data. What is the coefficient of friction during coitus for a penis without a foreskin, versus a similar size one with? It should require more force (in Newtons) to achieve penetration without a foreskin than with, if what the intactivists say is true. This should be measurable, so where are the measurements?

There aren’t any. In fact there seems to have been only one attempt to gather actual numerical data, but the experimental set up was so comical it is astonishing anyone could take it seriously. Yet intactivists do. Taves (2002) attempted to copulate with a hole cut in a Styrofoam cup, the cup being placed on a balance. He did this with his foreskin forward and retracted, and decided that the former required less force.

Whilst Taves is to be commended for at least trying to test the hypothesis, the idea that a hole in a Styrofoam cup is an accurate model for a human vagina is laughable. The design also failed to eliminate observer bias, not being conducted blind. For a detailed discussion of this pointless “study” and the dismayingly uncritical way it has since been cited, see Gross (2018). Now one can question the practicality of conducting such an experiment with live humans (although, perhaps, volunteers might be found), but modern sex toys come in all shapes and sizes, and many are designed to simulate the shape and texture of the relevant anatomical parts. Dildos with and without a “foreskin” are available so, in principle, it ought to be possible to set up an experiment using such devices and measure the force needed for one to penetrate the other (or for humans to take on one or other role with a counter-matching toy).

Interesting though such experiments might be, there is no need as there are other ways of testing the hypothesis, and they have already been done. The simplest is simply to ask subjects with experience of both kinds of penis about ease of penetration. An alternative is to use pain on intercourse (dyspareunia) as a proxy. If more force was required, then it could cause discomfort to one, or other, or both participants, or even cause injury (coital trauma) which, again, could serve as a proxy.

Both approaches have been used and, as usual, most studies fail to find an association, leaving the intactivists to cherry-pick mere opinion pieces, or a few weak, or even irrelevant, studies as in the above example. Looking at the best quality studies, in the top tiers of the hierarchy of evidence (see chart in http://circfacts.org/blog/#blog1 ) we have:

Cohort study (Feldblum et al., 2015, n = 194): 87.5 % of men reported sex was better after circumcision. 16.6 % found penetration was easier. The same number had less pain on intercourse or fewer coital injuries.

Case control/cohort study (Nordsrtom et al., 2017, n >3,000): less pain on intercourse for men after circumcision (p <0.001).

Case control/cohort study (Westercamp et al., 2017, n >3,000): fewer coital injuries in circumcised men (p <0.001).

Cohort study (Brito et al., 2017, n = 500): fewer coital injuries in men after circumcision (p <0.001).

Cohort study (Galukande et al., 2017, n = 304): easier penetration reported by 42.2 % of men after circumcision. The rest, presumably, no difference.

Randomized controlled trial (Kigozi et al., 2008, n = ca. 1,500 men): no difference in ease of penetration, or pain during intercourse, between circumcised and non-circumcised men.

Randomized controlled trial (Kigozi et al., 2009, n = 455 women): 97 % overall satisfaction with their partners’ circumcisions. Only one woman in the entire group of 455 reported pain on intercourse, which is not significant.

Randomized controlled trial (Krieger et al., 2008, n = 1,995 men): no difference in pain during intercourse for men whether circumcised or not.

Systematic review (Morris & Krieger, 2013): no difference in pain during intercourse for men whether circumcised or not.

Systematic review (Shabanzadeh et al., 2016): mostly no difference or a decrease, in pain during intercourse, associated with circumcision.

Systematic review & meta-analysis (Tian et al., 2013): no difference in pain during intercourse for men whether circumcised or not.

Systematic review & meta-analysis (Yang et al., 2018): less pain on intercourse for circumcised men.

Note also the large sample sizes (n) for some of the studies, and the inherently better study designs that exclude selection bias.

At the time of writing (January 2018) every single study in the top tiers (case-control upwards) of the hierarchy of evidence finds that circumcision either has no effect on dyspareunia or penetration, or actually improves matters. These studies are nearly all of men, but include one randomized controlled trial of women. Besides, if the men are finding it easier to penetrate, then it must be better for the women too.

The use of artificial lubricant, whether during coitus, or when going solo, has not been studied, which is unfortunate, given the frequency with which intactivists use the lubrication argument. They commonly point to allegedly greater use of artificial lubricants in the U.S. compared to non-circumcising countries but, when asked to back this up with actual sales figures, they tend to go quiet. In any case, even if it could be shown that U.S. men were more avid uses of lube, to claim without further evidence that this was due to circumcision would be to commit the ecological fallacy (http://circfacts.org/sloppy-logic/#slog10 ). They would need to show that circumcised males were using it more than non-circumcised ones.

This might be the case, however. Aside from anecdotal reports, there are Internet surveys that support this, at least where masturbation is concerned. Such surveys lack the scientific rigor of peer-reviewed papers, but they are all we currently have. One such, on the delightful jackinworld website (http://old.jackinworld.com/library/surveys/survey2.html ) found the following:

65.1 % of circumcised males masturbated dry, 34.9 % used lube

80.3 % of non-circumcised males masturbated dry, 19.7 % used lube

N = 603, 81.3 % from the U.S., mostly teenagers and young men. Date of survey: 1997.

Taking these results at face value it would appear that circumcised males do, indeed, use lube more often than non-circumcised ones, although two things are noteworthy.

  1. Most circumcised males do not use lube.
  2. A large minority of non-circumcised ones do.

But does this support the intactivists’ case? Well yes and no. It all depends on why some boys and men use lube when masturbating. Is it a cultural thing? Most of those males are American and it may just be a “given” in U.S. culture that one uses lube to enjoy a low five. And most American males happen to be circumcised. Or maybe they use it because it feels good, and feels even better for those who don’t have a foreskin in the way. Hence circumcised males may get a greater thrill out of lube than non-circumcised ones, and so use it more. Or maybe some use it because it helps, they find it harder without. In which case is it harder for circumcised or non-circumcised males?

It may, of course, be some combination, but the idea that a tight circumcision, leaving little mobility in the shaft skin, will create difficulties for masturbation that lube can ease is plausible, and supported by anecdotal accounts. Whilst this supports the intactivists’ claim up to a point, it is ultimately an argument for using circumcision techniques that result in a relatively loose circumcision, rather than an argument against circumcision per se. But then, there are men who have undergone revisions of their circumcisions in order to tighten things up down there, and there are Internet polls in which majorities of circumcised males express a preference for being tightly circumcised (https://www.misterpoll.com/polls/230256/results & https://www.misterpoll.com/polls/280655/results). So perhaps a tight circumcision is not so bad after all.

To sum up, the intactivists’ claims that foreskins aid penetration, or have a lubricating effect during coitus, are demonstrably false – as usual. But when it comes to use of lube for masturbation matters are less clear cut. What little evidence there is does not unambiguously support the intactivists’ cause, but it does seem a topic worthy of scientific study.

References
Brito, M.O., Khosla, S., Pananookooln, S., Fleming, P.J., Lerebours, L., Donastorg, Y., Bailey, R.C. (2017) Sexual pleasure and function, coital trauma, and sex behaviors after voluntary medical male circumcision among men in the Dominican Republic. J. Sex. Med., 14(4), 526-34. Abstract here:  https://www.ncbi.nlm.nih.gov/pubmed/28258953

Feldblum, P.J., Oketch, J., Ochieng, R., Hart, C., Kiyuka, G., Lai, J.J., Veena, V. (2015) Longer-term follow-up of Kenyan men circumcised using the ShangRing device. PLoS ONE 10(9), e0137510. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4569077/

Galukande, M., Nakaggwa, F., Busisa, E., Sekavuga Bbaale, D., Nagaddya, T., Coutinho, A. (2017) Long term post PrePex male circumcision outcomes in an urban population in Uganda: a cohort study. BMC Res. Notes, 10, 522. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5663120/

Gross (2016) Sex as the researcher intended it: A critique of the 1999 O’Hara and O’Hara circumcision study. On-line article: https://www.facebook.com/groups/elephantinthehospital/search/?query=O%27Hara

Gross (2018) The Styrofoam vagina. On-line article, updated in 2021: https://www.circumcisionchoice.com/single-post/styrofoamvagina

Kigozi, G., Lukabwe, I., Kagaayi, J., Wawer, M.J., Nantume, B., Kigozi, G., Nalugoda, F., Kiwanka, N., Wabwire-Mangen, F., Ridzon, R., Buwembo, D., Nabukenya, D., Watya, S., Lutalo, T., Nkale, J., Gray, R.H. (2009) Sexual satisfaction of women partners of circumcised men in a randomized trial of male circumcision in Rakai, Uganda. BJU Int., 104(11), 1698-701. https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1464-410X.2009.08683.x

Kigozi, G., Watya, S., Polis, C.B., Buwembo, D., Kiggundu, V., Wawer, M.J., Serwadda, D., Nalugoda, F., Kiwanuka, N., Bacon, M.C., Ssempijja, V., Makumbi, F., Gray, R.H. (2008) The effect of male circumcision on sexual satisfaction and function, results from a randomized trial of male circumcision for human immunodeficiency virus prevention, Rakai, Uganda. BJU Int., 101(1), 65-70. https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1464-410X.2007.07369.x

Krieger, J.N., Mehta, S.D., Bailey, R.C., Agot, K., Ndinya-Achola, J.O., Parker, C., Moses, S. (2008) Adult male circumcision: Effects on sexual function and sexual satisfaction in Kisumu, Kenya. J. Sex. Med., 5(11), 2610-22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3042320/

Morris, B.J., Krieger, J.N. (2013) Does male circumcision affect sexual function, sensitivity, or satisfaction?—A systematic review. J. Sex. Med. 10(11), 2644-57. https://www.ncbi.nlm.nih.gov/pubmed/23937309

Nordstrom, P.C., Westercamp, N., Jaoko,W., Okeyo, T., Bailey, R.C. (2017) Medical male circumcision is associated with improvements in pain during intercourse and sexual satisfaction in Kenya. J. Sex. Med., 14(4), 601-12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5388349/

Shabanzadeh, D.M., Düring, S., Frimodt-Møller, C. (2016) Male circumcision does not result in inferior perceived male sexual function – a systematic review. Dan. Med. J., 63(7), A5245. Abstract here: https://www.ncbi.nlm.nih.gov/pubmed/27399981

Taves, D.R. (2002) The intromission function of the foreskin. Medical Hypotheses, 59(2), 180-2. http://www.cirp.org/library/anatomy/taves1/

Tian, Y., Liu, W., Wang, J-Z., Wazir, R., Yue, X., Wang, K-J. (2013) Effects of circumcision on male sexual functions: a systematic review and meta-analysis. Asian J, Androl., 15(5), 662-6.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3881635/

Westercamp, N., Mehta, S.D., Jaoko, W., Okeyo, T.A., Bailey, R.C. (2017) Penile coital injuries in men decline after circumcision: Results from a prospective study of recently circumcised and uncircumcised men in western Kenya. PLoS ONE, 12(10): e0185917. https://doi.org/10.1371/journal.pone.0185917

Yang, Y., Wang, X., Bai, Y., Han, P. (2018) Circumcision does not have effect on premature ejaculation: A systematic review and meta-analysis. Andrologia, ePub ahead of print. Abstract here: https://www.ncbi.nlm.nih.gov/pubmed/28653427

The foreskin stores and releases pheromones

This claim can be traced at least as far back as 1998: “The inner prepuce contains … pheromones such as androsterone” (Fleiss et al., 1998) and has since become one of the supposed “16 functions of the foreskin” endlessly copied across the internet, and happily debunked here: https://www.circumcisionchoice.com/single-post/2017/04/11/The-16-Functions-of-The-Foreskin-is-a-silly-myth-anticircumcision-activists (see “function” 6).

As the authors of that debunking point out, the putative “pheromones” are produced all over the body, and there is no evidence that the foreskin makes any significant contribution to the whole.

It gets worse. The source given by Fleiss et al., (1998) for their assertion about androsterone does NOT say that it is present in, or in any way associated with, the prepuce (foreskin). In fact it does not even mention this or any part of the penis. It also describes androsterone as a “pig hormone” (Cohn, 1994). In short, the authors have made this claim up and assigned to it a citation that is irrelevant, a common ploy amongst pseudoscientists who rely on the fact that most readers will not check the references and, even if they did, this one is behind a paywall. See http://circfacts.org/sloppy-logic/#slog23

But there is a more fundamental problem than typical intactivist dishonesty. It has not been established that humans have pheromones at all! No one has convincingly demonstrated that the substances in question have any sexual effect whatsoever (Wyatt, 2015). And a recent study found that two of these putative “pheromones” have no such effect at all (Hare et al., 2017), thus pouring yet more cold water on an idea that has never been fully accepted.

In the absence of proof that humans even have pheromones, intactivist claims relating to them, like so many of their assertions, can (and should) be dismissed as baseless speculations.

References
Cohn, B.A. (1994) In search of human skin pheromones. Arch. Dermatol., 130(8), 1048-51. On-line abstract: https://www.ncbi.nlm.nih.gov/pubmed/8053704

Fleiss, P.M., Hodges, F.M., Van Howe, R.S. (1998) The immunological functions of the prepuce. Sex. Transm. Inf., 74(5), 364-7. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1758142/

Hare, R.M., Schlatter, S., Rhodes, G., Simmons, L.W. (2017) Putative sex-specific human pheromones do not affect gender perception, attractiveness ratings or unfaithfulness judgements of opposite sex faces. R. Soc. Open Sci., 4(3), 160831. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5383829/pdf/rsos160831.pdf

Wyatt, T.D. (2015) The search for human pheromones: the lost decades and the necessity of returning to first principles. Proc. Biol. Sci., 282(1804), 20142994. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375873/

The wonders of smegma

Smegma, popularly known as “cock-cheese”, is the foul-smelling accumulation of rotting skin cells and bacteria that builds up under the foreskins of males who do not wash down there. Point this out and point out also that circumcision automatically prevents its accumulation, and so is cleaner and more hygienic, and intactivists react scornfully. Just wash it away they say.

But in other polemics intactivists extol the wonders of smegma. It is a “natural emollient” that “protects and lubricates the glans and inner lamella of the prepuce, facilitating erection, preputial eversion, and penetration during sexual intercourse” (Fleiss et al., 1998).

It also “contains immunologically active compounds such as cathepsin B, lysozyme, chymotrypsin, neutrophil elastase,12 cytokines,13 and hormones such as androsterone.14 Lytic materials, such as lysozyme, which probably originates from the prostate and seminal vesicles, 9 destroy bacterial cell walls and inhibit and destroy Candidal species.15” (Van Howe & Hodges, 2006, copied from Fleiss et al., 1998).

Can’t they make up their minds? Wash it away, or keep this amazing natural lubricant with its additional immunological properties?

Dead skin cells continually slough off all external surfaces of the human body. Anyone who has worn a cast on a broken limb will have witnessed the impressive accumulation of dead skin when the cast is removed. As with a cast, under the foreskin the dead cells slough into a confined space. Unless regularly removed by washing they accumulate, and provide a nutritious meal for bacteria, snug in their warm, moist home.

Ultimately, that is all smegma is – dead and decaying skin cells (Parkash et al, 1973), providing a culture medium for bacteria. There is not a jot of evidence it has any “lubricating” effect. Where are the measurements showing that penetration is easier with a cheesy penis than with a clean one? And what is it supposed to “protect” the glans from? These are nothing but unsubstantiated speculations. Other claims about lubrication are debunked here: http://circfacts.org/function-sensation/#sens9

Claims of immunological function superficially look like they have evidentiary support. Until one checks the citations that is. As pointed out by critics (Waskett & Morris, 2008) none of the references given in the above quote support the assertion. They wrote: “their sources largely discuss gland secretions in general, not smegma nor the prepuce. A study (their ref. 9) cited to support ‘Lytic materials, such as lysozyme,’ being present did not mention lysozyme, and the presence in smegma of ‘prostate and seminal vesicle’ secretions is speculative. The preputial mucosa is ‘completely free of lanugo hair follicles, sweat and sebaceous glands,’ and there is ‘no evidence of any glandular tissue in the subpreputial region of the penis’.”

In their reply, Van Howe & Fleiss (2008) did not dispute this. In fact their references 12-15 do not even mention foreskins or smegma. They are irrelevant. Perhaps they know theirs’ was an example of misleading citations: http://circfacts.org/sloppy-logic/#slog23 a common and dishonest ploy by pseudoscientists relying on the fact that most people will not check the citations. As a further insult, the citation relating to androsterone describes it as a “pig pheromone” (Cohn, 1994).

Keeping smegma is definitely not healthy. Parkash et al. (1973) blame it for causing irritation and inflammation. It is also a likely risk factor for penile cancer (Misra et al., 2004), a link disputed by Van Howe & Hodges (2006). However their article was shown to be replete with errors, shaky statistics, unsupported assertions and ad hominems, in addition to the misleading citations already mentioned (Waskett & Morris, 2008). But that is to be expected from a pair of intactivists. In their reply (Van Howe & Hodges, 2008), they conceded one error, but largely ignored the main criticisms. Subsequent authors, who are not noted partisans in the circumcision debate, do accept that smegma likely puts males at risk of penile cancer (Larke et al., 2011; Marchionne et al., 2017). A meta-analysis provides further proof of the association (Morris et al., 2011).

So next time intactivists talk about hygiene and how simple it is to keep the penis clean, ask them why they attach so much value to the very substance that cleanliness eliminates.

(Image: circumcisionchoice.com)

References
Cohn, B.A. (1994) In search of human skin pheromones. Arch. Dermatol., 130(8), 1048-51. On-line abstract: https://www.ncbi.nlm.nih.gov/pubmed/8053704

Fleiss, P.M., Hodges, F.M., Van Howe, R.S. (1998) The immunological functions of the prepuce. Sex. Transm. Inf., 74(5), 364-7. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1758142/

Larke, N.L., Thomas, S.L., dos Santos Silva, I., Weiss, H.A. (2011) Male circumcision and penile cancer: a systematic review and meta-analysis. Cancer Causes Control, 22(8), 1097-110. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3139859/

Marchionne, E., Perez, C., Hui, A., Khachemoune, A. (2017) Penile squamous cell carcinoma: a review of the literature and case report treated with Mohs micrographic surgery. An Bras Dermatol., 92(1), 95-9. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5312186/

Misra, S., Chaturvedi, A., Misra, N.C. (2004) Penile carcinoma: a challenge for the developing world. Lancet Oncol., 5(4), 240-7. On-line: http://www.thelancet.com/pdfs/journals/lanonc/PIIS1470-2045(04)01427-5.pdf

Morris, B.J., Gray, R.H., Castellsagué, X., Bosch, F.X., Halperin, D.T., Waskett, J.H., Hankins, C.A. (2011) The strong protective effect of circumcision against cancer of the penis. Advances in Urology, 2011, article 812368. On-line: https://www.hindawi.com/journals/au/2011/812368/

Parkash, S., Jeyakumar, K., Subramanya, K., Choudhuri, S. (1973) Human subpreputial collection: its nature and formation. J Urol., 110(2), 211-2. On-line: http://www.cirp.org/library/anatomy/parkash/

Van Howe, R.S., Hodges, F.M. (2006) The carcinogenicity of smegma: debunking a myth. J Eur Acad Dermatol Venereol., 20(9), 1046-54. On-line: http://www.cirp.org/library/disease/cancer/vanhowe2006/

Van Howe, R.S., Hodges, F.M. (2008) In response to Waskett and Morris. J Eur Acad Dermatol Venereol., 22(1), 131-2. On-line (behind paywall): https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1468-3083.2007.02439.x

Waskett, J.H., Morris, B.J. (2008) Re: ‘RS Van Howe, FM Hodges. The carcinogenicity of smegma: debunking a myth.’ An example of myth and mythchief making? J Eur Acad Dermatol Venereol., 22(1), 131. On-line (behind paywall): https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1468-3083.2007.02439.x

Circumcision removes half the skin of the penis

March 2019

This, and variants thereof, are a recurring theme in intactivist propaganda.  For example:

“the foreskin has an average surface area of approximately 30–50 square centimetres … constituting roughly half of the moveable skin system of the penis” (Earp et al., 2018)

“Circumcision ablates what will become, in the adult, up to 90cm2 (~14in2) of tissue, approximately half of the skin the penis.” (DOC, 2016).

“Typical North American neonatal circumcisions remove what would constitute approximately 50% of the mean penile shaft skin length by adulthood.” (Hammond & Carmack, 2017).

The primary source, from which this claim is derived, is a paper by circumcision opponents, the late John Taylor and colleagues (Taylor, et al., 1996), but intactivists tend to misinterpret what Taylor et al. actually say.  Taylor et al. measured the foreskins (prepuces) on the bodies of 22 deceased adult men (aged 22-58).  The length of the outer surface of the foreskin was measured from its tip to the sulcus (the groove behind the rim of the glans).  The shaft skin was measured from the sulcus to the base of the penis (the abdominal wall).  The inner surface of the foreskin (the mucosa) was measured with the foreskin retracted.  The total length of penile skin they measured is therefore shaft skin + outer foreskin surface + inner foreskin surface (mucosa).  They noted that in circumcised men (number of subjects not stated) about 2 – 4 cm of mucosa remained, so they took an average of 3 cm as the amount of inner foreskin remaining in what they called “a residual mucosal cuff” in the circumcised adult male.

To understand where the “50%” figure (i.e. “half”) comes from it helps to reproduce the relevant paragraph in full:

“The mean length of prepuce in this sample was 6.4 cm (range 4.8-9.2) and covered 93% of the mean penile shaft (6.9 cm). Ten prepuces were as long as or longer than the shaft of the penis to which they belonged; three of them were > 10% longer than the shaft and glans combined. Circumcision of these subjects, allowing for a 3 cm mucosal cuff, would have removed a mean of 3.4 cm (range 1.8-6.2) of (strictly) preputial skin and mucosa, or 51% of the length of the mean adult penile shaft, or more from nearly half the penises.”

The paragraph is badly worded and contains an arithmetical error, although these don’t seriously affect the overall argument.  The prepuce (foreskin), by definition, does not cover 93% of the shaft, it covers the glans.  What the authors evidently mean is that in comparison to the shaft skin, the prepuce is (on average) 93% of the length of the shaft skin (6.4 cm is 93% of 6.9 cm).  The total length of penile skin would be 6.4 + 6.9 = 13.3 cm, in which case the foreskin is 48% of the total length of penile skin or, to be more precise, the moveable skin.  The surface of the glans is (mucosal) skin too and is ignored by the authors.

Circumcision removes the outer foreskin and some of the inner, but with an average of 3 cm of inner (mucosa) remaining, according to the authors.  According to their own measurements, circumcision would remove “a mean of 3.4 cm” (i.e. 6.4 cm of prepuce minus the 3 cm of mucosa that remains) of preputial skin and mucosa which, they say, is “51% of the length” of the shaft.  But the average shaft length was 6.9 cm.  3.4 cm is 49% of 6.9 cm, not 51%, so they got their sums wrong, albeit trivially.

So now we have two numbers – 48% & 51% (actually 49%) – that are the source of the “approximately 50%” or “roughly half” estimates bandied around uncritically by intactivists.  But wait a moment!  The way intactivists use this value is misleading (as usual).  The figures refer to the foreskin length as a % of the shaft length, NOT as a % of the total skin system of the penis.  This is a crucial point that intactivists deploying this argument often ignore as they imply (or even state outright) that it is half of the total skin that is being removed.

As explained above, using Taylor et al.’s own figures, the total skin length is 13.3 cm, and even then that does not include the glans.  It is the mobile skin (i.e. outer & inner foreskin + shaft).  Taylor et al. did not measure the glans skin, but we can surmise an average length of roughly 3 cm from sulcus to tip based on their observation that 12 of the prepuces did not reach the tip of the glans, the other 10 reached or passed it, and the average prepuce length (outer & inner surfaces combined) was 6.4 cm.

If circumcision removes 3.4 cm of foreskin (allowing for a 3 cm mucosal cuff) then 3.4 is 26% of 13.3 cm, nowhere near the 50% touted by intactivists.  However, as Taylor et al. point out, a proportion of shaft skin is also removed.  From a sample of just four dead circumcised infants, they estimated that 20 – 25% of the shaft skin was lost.  Erring in the intactivists’ favour, and assuming that these figures hold for adults, then 25% of the adult shaft skin length of 6.9 cm is lost along with the foreskin, i.e. 1.7 cm.  Thus, 3.4 cm of foreskin + 1.7 cm of shaft skin (= 5.1 cm) is lost from a total of 13.3 cm of skin.  That is 38% of the mobile skin; if we add on another 3 cm to account for the immobile glans skin, then it is 31% of the total skin.

38% and 31% are both considerably less than the “roughly half” claimed by intactivists, whether for mobile or total skin.  Some intactivists give a nod to these lower (and more accurate) figures, for example: “circumcision removes between one-third and one-half of the highly innervated penile skin system” (Svoboda, 2017) but they still like to get the “half” in too, even though, as we have seen, it is misleading – anything to make circumcision seem as bad as possible.  The quote from Hammond & Carmack (2017) at the start of this article manages to be technically correct, in so far as they acknowledge the 50% figure is relative to the shaft skin length but, of course, 50% sounds worse than thirty something percent, so guess which number they prefer.

So, once again an intactivist claim turns out to be based on misrepresentation.  It is also based on a small sample size (just 22 dead men), with (presumably) flaccid organs.  What would the figures be for erect ones?  Probably much lower, as the shaft would elongate but not the foreskin (which often retracts).  It also assumes that it even matters.  The empirical evidence from all the best studies indicates that circumcised men have as much sexual satisfaction and pleasure as their uncut peers, but with fewer health problems.  So that 31% or 38% of skin is clearly surplus to requirements, rendering the intactivist argument irrelevant.

References
DOC (2016) The sexual impact of circumcision.  Article on the website of “Doctors Opposing Circumcision”.  https://www.doctorsopposingcircumcision.org/for-professionals/sexual-impact/

Earp, B.D., Sardi, L.M., Jellison, W.A. (2018). False beliefs predict increased circumcision satisfaction in a sample of US American men. Cult. Health Sex. 20(8), 945-59.  https://www.ncbi.nlm.nih.gov/pubmed/29210334 (abstract only).  https://www.tandfonline.com/doi/suppl/10.1080/13691058.2017.1400104?scroll=top (appendix).

Hammond, T., Carmack, A. (2017) Long-term adverse outcomes from neonatal circumcision reported in a survey of 1,008 men: an overview of health and human rights implications. Int. J. Human Rights, 21(2), 189-218. https://www.tandfonline.com/doi/abs/10.1080/13642987.2016.1260007 (abstract only).

Svoboda, J.S. (2017) Nontherapeutic circumcision of minors as an ethically problematic form of iatrogenic injury. AMA J. Ethics, 19(8), 815-24.  https://journalofethics.ama-assn.org/sites/journalofethics.ama-assn.org/files/2018-04/msoc2-1708.pdf

Taylor, J.R., Lockwood, A.P., Cold, A.J. (1996) The prepuce: Specialized mucosa of the penis and its loss to circumcision. British J. Urology, 77(2), 291-5.  http://www.cirp.org/library/anatomy/taylor/

The foreskin has immunological functions

March 2019

An oft-repeated assertion is that the foreskin has immunological functions making it an important line of defence against invading pathogens. An early attempt to argue this was by Fleiss et al. (1998), a paper that is still cited by intactivists today. The authors are the notorious Paul Fleiss, source of the 20,000 nerves myth, HIV/AIDS denying quack, and convicted felon. Frederick Hodges, a jazz pianist, and Robert S Van Howe, whose meta-analyses on circumcision-related topics have all been comprehensively trashed. Not the most credible of sources.

As is to be expected their claims do not stand up. The key ones are demolished below.

“The sphincter action of the preputial orifice functions like a one way valve, blocking the entry of contaminants while allowing the passage of urine”.
In support they cite just two papers. The first, dating to 1916, merely speculates about the possibility of there being a sphincter but conceded, “there was no special collection of fibres such as might be thought to indicate a sphincter in any of the specimens I examined” (Jefferson et al., 1969). Not a good start.

The other paper they cite (Lakshmanan & Parkash, 1980) does not even mention the word “sphincter”. It does mention “free bundles of smooth muscle fibres arranged in a whorled pattern”, but it is a big jump from there to “sphincter”. Searching PubMed for “foreskin sphincter”, “prepuce sphincter” and “pretutial sphincter” finds not a single paper supporting the claim. In short, the “sphincter” claim is mere speculation, but that does not stop intactivists uncritically parroting it as established fact.

“Ectopic sebaceous glands concentrated near the frenulum produce smegma”.
To support this they scrape two old (1904 & 1932) and unobtainable (at least on-line) German papers out of their barrel, plus two others which do not support their claim. One of these (Hyman & Brownstein, 1969) actually contradicts the claim, saying that such glands “do not play a role in the production of smegma”. The other (Piccinno et al. 1990) is a report of a single boy whose case was described as “peculiar”. A few speculative assertions then follow about the wonders of smegma.

“The inner prepuce contains apocrine glands”.
No it doesn’t. Even the late John Taylor, darling of the intactivists, made no mention of them in his oft-cited (by intactivists) detailed histological descriptions of the foreskin (Taylor et al., 1996; Cold & Taylor, 1999). Parkash et al. (1973) made “a special search” for glandular tissue in their samples of foreskins and found none. The reference Fleiss et al. cite in support is a case report of two men who had apocrine cysts on their foreskins, it does not say those cysts were on the inner foreskin (Ahmed & Jones, 1969).

Fleiss et al. speculate about the bacterial flora and whether washing it away is a good idea. We now have hard data indicating that circumcision changes the biome of the glans in a beneficial way, reducing harmful anaerobic bacteria (Price et al., 2010). Time has proven Fleiss et al. wrong.

They try to claim that there is no difference in UTIs between circumcised and non-circumcised boys, cherry-picking one small study available only as an abstract, and ignoring many others that say the contrary. They assert that circumcised males have a higher rate of STIs without providing a jot of evidence, or any citation. They peddle the lubricating myth, and claim the circumcised organ is actually less hygienic, citing one of their own works (Van Howe, 1997) purporting to find cleanliness and other issues in young circumcised boys that nobody else has reported since.

Further tiresome speculations about innervation and desensitisation follow, leading to an argument that all this means that the circumcised man has to thrust harder and longer to trigger orgasm. Multiple studies since show this to be utter nonsense: circumcision has no adverse effect on any aspect of sexual function as confirmed by all the best quality studies (listed here). Building speculation on speculation they triumphantly conclude, “For this reason, a circumcised penis may be more likely than an intact penis to cause the breaks, tears, microfissures, abrasions, and lacerations in a vagina (or rectum) through which HIV in the thrusting partner’s semen could enter the receiving partner’s bloodstream.”

Happily we now have actual data from two high quality (case control/cohort) studies with large sample sizes, showing that this claim is not only utterly and completely false, it is the exact reverse of reality. Circumcised males experience fewer coital injuries than their non-circumcised peers, thereby reducing their chances of infection (Brito et al., 2017; Westercamp et al., 2017). Time has proven Fleiss et al. wrong.

They continue their speculations with an attack on the HIV/foreskin link, but this has since been comprehensively established to the point of consensus amongst all medical bodies dealing with the epidemic. Again, time has proven Fleiss, Hodges and Van Howe wrong.

They assert, “neonatal circumcision immediately compromises the immune system, making the circumcised male neonate vulnerable to infection, often with tragic consequences” citing two papers referring to infections of the fresh circumcision wound as complications. But this can happen to any wound and is not a result of the immune system being compromised. Thankfully it is uncommon with circumcision, and serious infections are rare. One of the papers they cite actually says that most of these infections “are of little consequence and settle with local treatment” (Williams & Kapilla, 1993). The infant is more likely to die of a UTI that circumcision prevents, than of an infection from a circumcision wound (Wiswell & Geschke, 1989) a fact available to the authors, but which they chose to ignore.

In short, the principal paper on which the “immunological functions” claim is based is speculation and nonsense from start to finish. Many of the citations do not support the claims, and subsequent research has refuted many of the assertions. This does not stop intactivists persevering with the claim, and attempting to support it with scientific papers. At best these attempts are misleading half-truths. One such, about langerin, is debunked here.

Thanks to the HIV/foreskin connection, a great deal of research has been done on the immunology of foreskins. For reviews see Morris & Wamai (2012), Jayathunge et al., (2014), and Esra et al. (2016). One of the main mechanisms identified by which HIV gains entry is via Langerhans cells. These are immune system cells present at the inner surface of the foreskin, and which are targeted by HIV. How ironic that it should be a part of the immune system that really is present in foreskins that increases males’ vulnerability to HIV.

Other immune system cells are present too, as they are also in other parts of the penis (Anderson et al., 2011; Sennepin et al., 2017). But then immune system cells are present in skin all over the body (Matejuk, 2017). The skin is often the first line of defence against germs, so it would be astonishing if it was not rich in immunological activity.

So yes, there are immune system-related cells and their associated biochemicals in the foreskin, just as there are in all human skin. But it no more follows from this observation that the foreskin has immune functions beyond those of any other piece of skin, or that we will suffer without them. One might as well argue that the presence of blood vessels in the foreskin means it has circulatory functions. One might also ask: if the foreskin is so immunologically important then why are males lacking one less prone to so many infections? The entire argument is a red herring.

References
Ahmed, A., Jones, A.W. (1969) Apocrine cystadenoma: a report of two cases occurring on the prepuce. Br. J. Dermatol., 81(12), 899-901. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2133.1969.tb15971.x?sid=nlm%3Apubmed (abstract only).

Anderson, D., Politch, J.A., Pudney, J. (2011) HIV infection of the penis. Am. J. Reprod. Immunol., 65(3), 220-9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3076079/

Brito, M.O., Khosla, S., Pananookooln, S., Fleming, P.J., Lerebours, L., Donastorg, Y., Bailey, R.C. (2017) Sexual pleasure and function, coital trauma, and sex behaviors after voluntary medical male circumcision among men in the Dominican Republic. J. Sex. Med., 14(4), 526-34. https://www.ncbi.nlm.nih.gov/pubmed/28258953 (abstract only).

Cold, C.J., Taylor, J.R. (1999) The prepuce. BJU Int. 83, Suppl. 1:34-44. http://www.cirp.org/library/anatomy/cold-taylor/

Esra, R.T., Olivier, A.J., Passmore, J-A.S., Jaspan, H.P., Harryparsad, H., Gray, C.M. (2016) Does HIV exploit the inflammatory milieu of the male genital tract for successful infection? Front. Immunol., 7, article 245. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4919362/

Fleiss, P.M., Hodges, F.M., Van Howe, R.S. (1998) Immunological functions of the human prepuce. Sex. Transm. Inf., 74(5), 364-7. On-line: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1758142/

Jayathunge, P.H.M., McBride, W.J.H., MacLaren, D., Kaldor, J., Vallely, A., Turville, S. (2014) Male circumcision and HIV infection: What do we know? Open AIDS J., 8, 31-44. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4192839/

Jefferson, G., Lond, M.S., Victoria, B.C. (1916) The peripenic muscle: some observations on the anatomy of phimosis. Surgery, Gynecology & Obstetrics (Chicago), 23(2), 177-81. http://www.cirp.org/library/anatomy/jefferson/

Lakshmanan S., Parkash S. (1980) Human prepuce: some aspects of structure and function. Indian J. Surg., 44, 134-7. http://www.cirp.org/library/anatomy/lakshmanan/

Matejuk, A. (2018) Skin immunity, Arch. Immunol. Ther. Exp., 66(1), 45-54. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5767194/

Morris, B.J., Wamai, R.G. (2012) Biological basis for the protective effect conferred by male circumcision against HIV infection. Int. J. STD AIDS, 23(3), 153-9. https://www.ncbi.nlm.nih.gov/pubmed/22581866

Parkash, S., Jeyakumar, K., Subramanya, K., Choudhuri, S. (1973) Human subpreputial collection: its nature and formation. J Urol., 110(2), 211-2. http://www.cirp.org/library/anatomy/parkash/

Piccinno, R., Carrel, C-F., Menni, S., Brancaleon, W. (1990) Preputial ectopic sebaceous glands mimicking molluscum contagiosum. Acta Derm Venereol., 70, 344–5. https://www.ncbi.nlm.nih.gov/pubmed/1977263 (abstract only).

Price, L.B., Liu, C.M., Johnson, K.E., Aziz, M., Lau, K.L., Bowers, J., Ravel, J., Keim, P.S., Serwadda, D., Wawer, M.J., Gray, R.H. (2010) The effects of circumcision on the penis microbiome. PLoS ONE, 5(1), e8422. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0008422

Sennepin, A., Real, F., Duvivier, M., Ganor, Y., Henry, S., Damotte, D., Revol, M., Cristofari, S., Bomsel, M. (2017) The human penis is a genuine immunological effector site. Front. Immunol., 8, article 1732. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5735067/

Taylor, J.R., Lockwood, A.P., Taylor, A.J. (1996) The prepuce: specialized mucosa of the penis and its loss to circumcision. Br J Urol., 77(2), 291-295. http://www.cirp.org/library/anatomy/taylor/

Van Howe, R.S. (1997) Variability in penile appearance and penile findings: a prospective study. Brit J Urol., 80(5), 776-782. http://www.cirp.org/library/complications/vanhowe/

Westercamp, N., Mehta, S.D., Jaoko, W., Okeyo, T.A., Bailey, R.C. (2017) Penile coital injuries in men decline after circumcision: Results from a prospective study of recently circumcised and uncircumcised men in western Kenya. PLoS ONE, 12(10): e0185917. https://doi.org/10.1371/journal.pone.0185917

Williams, N., Kapila, L. (1993) Complications of circumcision. Brit J Surg., 80(10), 1231-6. http://www.cirp.org/library/complications/williams-kapila/

Wiswell, T.E., Geschke, D.W. (1989) Risks from circumcision during the first months of life compared with those for uncircumcised boys. Pediatrics, 83(6), 1011-15. https://pediatrics.aappublications.org/content/83/6/1011 (abstract only).