What The Science Says About Circumcision: Part 1 — The Benefits

Note: This should go without saying, but the article below refers to male circumcision. Female circumcision is a completely separate practice, occurring for the express purpose of destroying sexual function. That the two practices share a name in common is unfortunate and misleading.

This is part 1 of a three-part series. Part 2 will deal with the scientific evidence as it pertains to risks associated with circumcision, and part 3 will deal with making sense of the circumcision-related rhetoric. It’s taken me a while to get up the guts to write an article on what the science says about circumcision, because it’s such an emotionally charged issue. I didn’t have to deal with the circumcision decision personally, since W is a girl. However — and perhaps at least in part because I didn’t have to deal with the decision — I can approach the science in a completely unemotional manner, and I think there’s value in so doing.

Here’s the thing; unlike many other parenting decisions that can be made based solely upon the science, circumcision is a decision that is (nearly by necessity) based upon emotion, morals, and values. Why? Two reasons. First, in the U.S., there’s no medical justification for doing the procedure, but there’s a major values-based justification for circumcision among many prevalent religious groups. Second, there’s no scientific evidence that routine circumcision causes harm and should be avoided, but many parents feel emotionally uncomfortable with the idea of removing a part of their baby’s body.

In the end, there are three points I’m trying to make with this article:

1) Circumcision is a very sensitive issue BECAUSE values are so wrapped up in the decision.

2) It’s fine to make a decision based upon values, but it’s important to recognize when a decision is values-based rather than evidence-based, and it’s critically important to avoid pretending that there is evidentiary support for a decision if, in fact, there’s not.

3) There is no strong evidence either FOR or AGAINST routine circumcision of boys in the U.S.

On to the science. There are several arguments that have historically been given in support of circumcision. Among these, there’s the argument that circumcision helps reduce the risk of HIV infection. There is actually reasonable scientific support for this assertion; a variety of studies (mostly conducted in Africa) have found that circumcision helps reduce the risk of acquiring the disease by somewhere in the range of 50-60% (see, for instance, Auvert et al, Bailey et al, Gray et al). In the Auvert, Bailey, and Gray studies, participants were recruited from among uncircumcised men. Those randomly assigned to the treatment group were circumcised (with their permission), while those randomly assigned to the control group were left uncircumcised (though they were offered the option of circumcision at the conclusion of the study). The randomization of the subjects allows for drawing causal (rather than correlational) conclusions; that is, because of the study design, we can say circumcising men helps reduce the risk of HIV. Correlationally, Bongaarts et al found that across 409 African ethnic groups, circumcision practices were 90% correlated with prevalence of HIV, indicating a significantly reduced risk of HIV among circumcised males.

Meta-analysis of studies on circumcision and HIV infection also reveal a correlation between circumcision and reduced risk of HIV (a meta-analysis is a study of the results of many different studies). Weiss et all looked at 27 studies of HIV and circumcision in Africa, and found that the vast majority of studies showed a significantly (about 50%) reduced risk of HIV. The reduced risk was even more significant (about 70%) in men at high risk for HIV infection. Similarly, Moses et al noted that a “substantial” body of evidence links circumcision to reduced risk of HIV.

Why would circumcision reduce the risk of HIV infection?  A study published in the British Medical Journal suggests that there is a high concentration of specialized cells that happen to have HIV receptors on the inside of the foreskin. These cells are a potential entry-point for the HIV infection (Szabo et al). The authors recommend routine circumcision in areas with high HIV prevalence. The World Health Organization (WHO) is convinced by the preponderance of evidence that circumcision is recommended in areas with high HIV prevalence. It’s worth noting, incidentally, that WHO is the same organization that recommends breastfeeding until at least 2 years of age, lest the reader be tempted to label the organization as “overly Western” too quickly.

Unfortunately, while there’s lots of evidence to support male circumcision in areas of epidemic HIV, the evidence doesn’t help inform scientific decision-making on circumcision in the U.S. The lower prevalence of HIV in the U.S. reduces the risk of HIV to such an extent that it’s no longer clear whether circumcision is justified solely as a means of HIV risk-reduction. The U.S. Centers for Disease Control and Prevention (CDC), for instance, doesn’t recommend circumcision solely for the purpose of HIV risk-reduction (though they are considering recommending the procedure for uncircumcised homosexual men).

There’s also been some suggestion that circumcision reduces the risk of contracting HPV (human papillomavirus), which is linked to cervical cancer in women, and which can be transmitted to a woman through sexual intercourse with an HPV-infected man. Several studies have found a correlation between circumcision and reduced risk of HPV infection. Castellsagué et al found in a sample of men that those who were uncircumcised were four times more likely to have HPV than circumcised men. Further, monogamous women with uncircumcised male partners were more likely to contract cervical cancer than monogamous women with circumcised male partners, even when the circumcised males had a history of six or more sexual partners. Similarly, Tobian et al found a reduced risk of HPV in circumcised men. Neither of these studies was randomized or controlled, however, meaning that while it’s possible to say that being circumcised is associated with reduced risk of contracting HPV, the studies don’t allow us to say that being circumcised causes reduced risk of contracting HPV.

However, there are also randomized studies that shed causal light on the relationship between circumcision and HPV. Auvert et al, Gray et al and Wawer et al all demonstrated that when HIV-negative, uncircumcised men were randomly assigned to be circumcised (with their consent) or remain uncircumcised, those who were circumcised were less likely to contract HPV. Gray noted that circumcision not only decreased the likelihood of contracting HPV, it increased the likelihood of clearing the infection from the body in the case of contraction. Wawer examined both the men and their female partners at a 24-month follow-up; the partners of the circumcised men were significantly less likely to have HPV infection at the time of the follow-up than the partners of the uncircumcised men. On the basis of the evidence, it’s reasonable to say that male circumcision reduces the risk of HPV in both males and in their female partners. Still, with an HPV vaccine available on the market, male circumcision isn’t the only way to achieve a reduced risk of HPV, so it can’t be recommended purely on that basis.

There are a number of studies that suggest male circumcision also reduces the risk of penile cancer, which is relatively rare in the U.S. Typically, cancerous changes begin on the glans (tip) of the penis or on the foreskin, and infection with HPV increases the risk of cancer development, according to the U.S. National Library of Medicine. Penile cancer is much more prevalent in countries with a low circumcision rate, including Africa and South America, explains the American Cancer Society. While the exact cause of penile cancer isn’t known, the accumulation of smegma under the foreskin of an uncircumcised man may increase the risk. Several studies have correlated increased risk of penile cancer with having an intact foreskin (see, for instance, Maden et al, Schoen et al, Tseng et al). The Tseng study suggests that the risk of penile cancer is most strongly associated with phimosis, which is a condition in which the foreskin doesn’t retract appropriately.

While the relationship between circumcision and reduced risk of penile cancer is well established, there isn’t enough data at the present time to recommend routine circumcision for the sole purpose of preventing penile cancer. In part, this is because penile cancer is so rare in the U.S. However, the cancer is most common in men age 60 and older, and circumcision rates have historically been quite high in the U.S., with 80-90% of men born in the 1940s through 1970s circumcised (Laumann et al, Xu et al). Recently, rates of circumcision in the U.S. have been falling somewhat, with the CDC estimating just over 50% of males circumcised in-hospital in 2010 (MMWR). It remains to be seen whether the penile cancer rate will increase in the coming decades concomitantly with these men reaching the prime age for development of penile cancer.


Science Bottom Line:* There is no scientific evidence that strongly supports circumcision in the United States for the sole purpose of preventing disease.**


**Obviously, this is not to say that there’s no reason to circumcise, nor is it to say that there’s no SCIENTIFIC reason to circumcise in areas with epidemic HIV, etc. The point here is that the argument FOR circumcision in the U.S. can’t be made on the basis of scientific evidence, and must instead be made on the basis of values and beliefs.


What do you think about what the science shows?



Auvert et al. Randomized, controlled intervention trial of male circumcision for reduction of HIV infection risk: the ANRS 1265 Trial. PLoS Med. 2005 Nov;2(11):e298. Epub 2005 Oct 25.

Auvert et al. Effect of Male Circumcision on the Prevalence of High-Risk Human Papillomavirus in Young Men: Results of a Randomized Controlled Trial Conducted in Orange Farm, South Africa. J Infect Dis. 2009 Jan 1;199(1):14-9.

Bailey et al. Male circumcision for HIV prevention in young men in Kisumu, Kenya: a randomised controlled trial. Lancet. 2007 Feb 24;369(9562):643-56.

Bongaarts et al. The relationship between male circumcision and HIV infection in African populations. AIDS. 1989 Jun;3(6):373-7.

Castellsagué et al. Male circumcision, penile human papillomavirus infection, and cervical cancer in female partners. N Engl J Med. 2002 Apr 11;346(15):1105-12.

CDC. Trends in in-hospital newborn male circumcision–United States, 1999-2010. MMWR Morb Mortal Wkly Rep. 2011 Sep 2;60(34):1167-8.

Gray et al. Male circumcision for HIV prevention in men in Rakai, Uganda: a randomised trial. Lancet. 2007 Feb 24;369(9562):657-66.

Gray et al. Male circumcision decreases acquisition and increases clearance of high-risk human papillomavirus in HIV-negative men: a randomized trial in Rakai, Uganda. J Infect Dis. 2010 May 15;201(10):1455-62.

Laumann et al. Circumcision in the United States. JAMA 1997;277(13):1052-7.

Maden et al. History of Circumcision, Medical Conditions, and Sexual Activity and Risk of Penile Cancer. J Natl Cancer Inst. 1993 Jan 6;85(1):19-24.

Moses et al. The association between lack of male circumcision and risk for HIV infection: a review of the epidemiological data. Sex Transm Dis. 1994 Jul-Aug;21(4):201-10.

Schoen et al. The Highly Protective Effect of Newborn Circumcision Against Invasive Penile Cancer. Pediatrics. 2000 Mar;105(3):E36.

Szabo et al. How does male circumcision protect against HIV infection? BMJ. 2000 Jun 10;320(7249):1592-4.

Tobian et al. Male Circumcision for the Prevention of HSV-2 and HPV Infections and Syphilis. N Engl J Med. 2009 Mar 26;360(13):1298-309.

Tseng et al. Risk Factors for Penile Cancer: Results of a Population-based Case–Control study in Los Angeles County (United States). Cancer Causes Control. 2001 Apr;12(3):267-77.

Wawer et al. Effect of circumcision of HIV-negative men on transmission of human papillomavirus to HIV-negative women: a randomised trial in Rakai, Uganda. Lancet. 2011 Jan 15;377(9761):209-18. Epub 2011 Jan 6.

Weiss et al. Male circumcision and risk of HIV infection in sub-Saharan Africa: a systematic review and meta-analysis. AIDS. 2000 Oct 20;14(15):2361-70.

Xu et al. Prevalence of circumcision and herpes simplex virus type 2 infection in men in the United States: the National Health and Nutrition Examination Survey (NHANES), 1999-2004. Sex Transm Dis. 2007 Jul;34(7):479-84.


23 Comments (+add yours?)

  1. Megyn @Minimalist Mommi
    Feb 01, 2012 @ 20:22:51

    I think by your conclusion, the same conclusion could be made about vaccinations for the US. The amount of people getting diseases we often vaccinate against are in low occurrence in the US. Does this mean there is no need to vaccinate in our situation? I think that’s for each to decide. We do vaccinate and we did circumcise. And I would not change either of those decisions 🙂

    • SquintMom
      Feb 02, 2012 @ 03:07:21

      I think there’s actually a major difference, however; HIV can be prevented in ways aside from circumcision, while vaccinations are the only way to prevent diseases like measles.

      • Hugh7
        Feb 14, 2012 @ 23:41:16

        Not only that, but measles, whooping cough and diphtheria are now rare precisely because of previous vaccination campaigns, and where they slacken off, epidemics recur – and measles is ferociously contagious and can be fatal.

        Not so circumcision. The diseases for which it is supposed to be preventative – including female-to-male transmission of HIV – are all so rare, and/or the degree of protection it offers is so slight, that it would take many circumcisions to prevent even one case.

      • SquintMom
        Feb 15, 2012 @ 00:59:02

        It’s actually male-to-male HIV transmission for which circumcision is most effective, which is why the CDC has considered recommending it as an adult procedure for homosexual men. The protection, however, is quite significant, particularly in epidemic areas, which is why the WHO recommends male circumcision in Africa. HPV transmission is also quite significantly reduced by circumcision.

      • Allan
        Apr 21, 2012 @ 17:01:25

        You are totally kuku! Male to male sex is the area where it is acknowleged by all camps that circumcision is of NO benefit. If you got that wrong I cant take seriously anything else you have said

      • SquintMom
        Apr 22, 2012 @ 16:28:22

        Your source for that? “Acknowledged” is not the same as “scientific fact.” That the Earth is flat is acknowledged by some. Doesn’t make it true.

  2. Hugh7
    Feb 02, 2012 @ 01:46:47

    While your article seems to be going to try hard to be dispassionate, your references so far betray a strong bias towards circumcision. Schoen, for example, thinks it’s an “American” thing to do. (When he said this at Berkeley, the students laughed at him. In all probability, none of the Founding Fathers or Presidents before Eisenhower were circumcised.)

    Slight reductions in either rare and treatable conditions like urinary tract infections (commoner in girls) or vanishingly rare conditions of old age like penile cancer, do not, um, cut it.

    “It remains to be seen whether the penile cancer rate will increase in the coming decades concomitantly with these men reaching the prime age for development of penile cancer.” Why should it? The penile cancer rate in non-circumcisng Denmark is about 2/3 that of the USA.

    HIV? The evidence is debatable, it only applies to female-to-male transmission, one of the rarer directions, and the window period when he could contract it sexually before he was old enough to give his own consent to surgery is very short. Bongaarts may have found a coorelation between circumcision and low HIV in populations, but USAID found no such correlation on a man-against man basis – in 10 out of 18 countries for which data is available, more of the CIRCUMCISED men were HIV+.

    You are right that this is not a purely scientific matter, but step back a minute and ask, why would anyone in their right mind want to cut part off somebody’s else’s genitals if there were not a pressing medical need to do so? Such a pressing need that it could not wait for their own informed consent? Something very irrational is going on here (just as irrational as with FGC, for which many other reasons are given than the one you cite). The rest of the English-speaking world tried circumcising, found it did no good, and has virtually given it up, with no epidemics of any of the diseases it was supposed to be good for. The rest of the developed world has never considered circumcising.

    I wait to see what you mean by “values”. Do you include the value of autonomy for the individual whose genitals they are?

    • SquintMom
      Feb 02, 2012 @ 03:15:42

      The purpose of the SquintMom website (and this post) is to discuss the scientific evidence surrounding parenting issues. You make a number of emotional and values-based arguments, but unless you can cite legitimate, well-conducted scientific research to back up your arguments, it’s impossible to have an evidence-based discussion.

      However, you make legitimate values-based points; as I state several times in this article (and will reiterate throughout this series), the decision to circumcise is based solely upon values. No existing scientific evidence makes a strong case for or against circumcision.

  3. Trackback: What The Science Says About Circumcision: Part 2 — The Risks | SquintMom.com
  4. Trackback: Options, Ethics, and Moral Imperatives | SquintMom.com
  5. Dorit Reiss
    May 21, 2012 @ 15:51:37

    This is not a comment, it’s a sincere request for more information: can you say something about the claimed benefits in reducing urinary tract infections (mentioned by a commentator, but not by you) and general reduction of infections? (These are mentioned in other sources, but frankly – I don’t trust these, don’t have direct access to medical databases and trust you more).

    • SquintMom
      May 22, 2012 @ 13:24:16

      I’ll look into this. Send me an email and remind me if I don’t post more in the next week or so.

  6. Trackback: Spanking Associated With Development Of Mental Disorders, New Study Suggests | SquintMom.com
  7. Maria
    Jul 26, 2012 @ 07:22:36

    You know, the science is pretty neutral on earlobe amputation. Earlobes, unlike foreskin, serve no bodily purpose & ears can get infected & damaged in sports. Hearing is largely internal, and I see no scientific evidence to suggest having ears is beneficial. So, from evidence-based research, it’s totally value based if I want to amputate my child’s ears without immediate medical indication.

    • SquintMom
      Jul 26, 2012 @ 08:14:15

      Actually, no, it’s not. For the science to be neutral, there would have to be proof of benefits that were approximately in balance with proven risks. This is not the case.

      • Maria
        Jul 28, 2012 @ 11:11:34

        Well then the case for circumcision neutrality can neither be balanced with the risk, since male children have and do still die from genital cutting. Some lose their entire penises, others are irreparably damaged. There are also reports of children having heart attacks, going into shock, among other psychological risks. The ‘benefits’ of circumcision MUST be balanced with the risk of death, infection, skin bridges, adhesions, and other complications often not present until adulthood (such as shaft hair and bowed erections from too much skin being removed to accommodate the adult penis.)

        I also think your arguments could be compared to female cutting, anagalous to male cutting, which is the removal of the female prepuce also known as clitoral hood. I’ve read studies showing a decrease in HIV risk among cut women, as well as studies showing women can enjoy sex & many have very positive views on sex. There are even studies published in the 1970’s in the U.S. which show medical benefits from cutting girls.

        So I was curious if you would do a series on female cutting, examining the scientific evidence of prepuce removal of girls? Because if we can come to the same conclusions as we do with male cutting, omitting cultural psychosexuality, values, morality and ethics, then it seems as though we either need to ban both or ban neither.

        Coincidentally, the AAP released a statement in 2010 suggesting doctors be permitted to perform a ritual knick of girls whose parents wished to have circumcised. (they quickly recanted but the report is still available for reading) It was and is difficult for doctors to explain to parents why they may cut their sons but not their daughters. Given the medical evidence.

      • SquintMom
        Jul 28, 2012 @ 12:04:17

        No, I’m sorry; female genital cutting and male genital cutting are not analogous. The fact that they’re both called “circumcision” is in no way a reference to removal of the same tissues. The male foreskin comes from the same tissue as the hood of the clitoris. Even the most conservative female cutting removes the clitoris in its entirety; the analogous male procedure would take the entire glans of the penis (head) in addition to the foreskin. As no such procedure is done routinely amongst infant males in the U.S., the comparison is simply invalid.

        Incidentally, the most common female cuttings take the labia minora as well, which are analogous to (same tissue as) the shaft of the penis. Some even take the labia majora, which is the same tissue as the scrotum. So you see, there’s simply no comparison.

      • Maria
        Jul 28, 2012 @ 12:59:15

        Actually you are misinformed. The clitoris is mostly an internal organ, and cutting the hood off or even the external clitoris, which is common as well, does little to impair sexual function, as a recent Swedish study revealed, which is why cut women can still orgasm. Cutting girls also has little effect on their ability to reproduce. Further, the WHO rates severity of cutting by damage done, and male forekin excision is rated more damaging than hoodectomy. Still even less damaging forms of female cutting, even when relatively benign (such as the AAP recommended ritual knick) are abhorred and seen as gross violations of human rights. For some reason the same thinking is not given to our sons’ healthy genitals.

        We don’t look at girls and ask, I wonder what sort of medical benefits cutting off their clitorises might prevent because that’s just bad medicine. Same is true of foreskin. Same is true of every healthy, normally occurring, functioning body part of our children.

        You also failed to address risk of death or loss of penis or the fact the AAP recommended cutting girls on the basis of it being less damaging than foreskin excision.

      • SquintMom
        Jul 29, 2012 @ 11:59:52

        You should publish the research you’ve conducted that shows that the clitoris is NOT homologous to the glans of the penis, as it overturns decades of embryological work and flies in the face of all the anatomy and physiology taught in modern medicine. Congratulations on your groundbreaking work!

  8. Laney
    Jul 29, 2012 @ 12:17:19

    Jeezuz H Christ, SquintMom, how do you manage to keep from telling people like Maria what FREAKING IDIOTS they are!? Doesn’t it just KILL you!? At least you finally got sarcastic.

    Here, I’ll do it for you. Maria, you’re an IDIOT. What planet are you from? Have you ever studied embryology? Do you even know what the word means? Let me define it for you: it’s the study of development, and includes analysis of tissue origins.

    Obviously, your ability to understand multisyllabic words (not to mention complex concepts) is limited, so I’m going to explain this in really easy, simply-constructed sentences:

    The glans (that’s the head, in case I’ve already lost ya, darlin’) of the penis in the male comes from the same tissue (not Kleenex, sweetie…try to stay with me: tissues in the human body are groupings of cells that share a similar purpose) as the clitoris in the female. The foreskin of the penis comes from the same tissue as the hood of the clitoris. They share similar functions and are innervated (that’s a big word, I know…I tried to find a smaller one for you, but golly gee…anatomy is HARD! Anyway, innervated refers to the nerves that connect to a tissue) with the same nerves.

    Maria, let me tell you a secret. No one who actually knows what research is EVER refers to “looking up random shit on the Internet” as research. Consequently, reading the inane ramblings of ideological idiots who happen to believe what you believe doesn’t make you well-informed. But then, I guess the beauty (or fatal flaw, depending upon how you look at it) of the internet is that it allows idiots of every shape and flavor to meet those few like-minded idiots out there, so they can validate each other.

    Say hi to the other members of the flat-Earth society for me, will ya? Enjoy the Koolaid, and don’t forget that your tinfoil hat looks best tipped at a jaunty angle.


    • SquintMom
      Jul 29, 2012 @ 12:20:53

      Laney, I really shouldn’t have approved your comment, because I typically don’t allow stuff like this through…but it made me laugh so hard milk came out my nose, so…try to be nice from now on, ok?

  9. Maria
    Jul 30, 2012 @ 05:38:50

    Since you are censoring me here, Kirsten, I’d be happy to debate you on the open platform of twitter. I sent you some tweets. You aren’t the only one who can be snarky & in this case you are grossly biased by your own ethnocentric world view. When you are ready to debate in an equitable forum, you will be able to find me.

    • SquintMom
      Jul 30, 2012 @ 10:53:57

      I’m not censoring you; I approved your comment intact and unedited. However, I am not interested in debating this issue. I am neither pro- nor anti-circumcision, and therefore without a strong view of my own to which I am particularly attached and which I wish to defend, it’s not worth my time to engage in a debate. Thanks for your comments.

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