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.