Research Update II: Male Circumcision

Fall 2011

Recent research suggests that male circumcision can reduce the risk of HIV infection for heterosexual men in countries that have high rates of HIV among heterosexual people. What does this mean for gay men and other men who have sex with men (MSM)?

How Can Circumcision Reduce HIV Infection?

The foreskin is a major route that HIV can use to enter the body and cause infection. There are two reasons for this. Firstly, the foreskin is a delicate tissue that can tear during sex. These tears can make it easier for the virus to enter the body. Secondly, the foreskin has a high number of a certain kind of immune cell that HIV likes to infect, known as HIV target cells.1 The more HIV target cells there are, the more likely HIV will find one to infect. Therefore, the removal of the foreskin through circumcision makes it more difficult for HIV to find a way into the body and to cause infection.

Male Circumcision Works for Heterosexual Men in Africa

We now know that male circumcision, when accompanied with safer sex counselling on condom use and reducing the number of sexual partners, can help protect HIV-negative men from becoming infected with HIV through vaginal sex with an HIV-positive woman. Three randomized controlled trials conducted in Eastern and Southern Africa found that circumcised heterosexual men were approximately 60% less likely to become infected with HIV than uncircumcised men.2-4


What About Circumcision for Men Who Have Sex With Men?

If circumcision works for heterosexual men in Africa, can it also work for MSM in Canada? The simple answer is no. Studies have found that male circumcision does not reduce the risk of HIV transmission among gay men.5

Why? One would expect that, in the same way that circumcision provides some protection to HIV-negative men who have insertive vaginal sex, circumcision would provide some protection to HIV-negative men who have insertive anal sex (also known as "topping"). However, many MSM are not only tops (the insertive partner) -- but also bottoms (that is, they also have receptive anal sex). Male circumcision would not protect an HIV-negative man when he bottoms because in this case HIV would enter through the anus or rectum, and not the foreskin of the penis. In addition, because the risk is so much higher when a man bottoms than when he tops,6 circumcision may not protect him even if he bottoms only occasionally.

To understand this more fully, some studies have been conducted to investigate whether or not circumcision is protective for men who mostly, or only, top during anal sex. The few studies that have been completed to date have been inconclusive -- with some studies suggesting that male circumcision is protective for men who only top, while other studies suggest otherwise.7 However, a recent review that combined the results of these studies suggests that male circumcision is protective for men who mainly top.8

The Verdict

Male circumcision can protect straight men who are only exposed to HIV on the penis, but it does not seem to be effective for HIV prevention in MSM. While circumcision might provide some protection for gay men who only top, the degree of protection (if any) has yet to be determined.


  1. McCoombe SG, Short RV. Potential HIV-1 target cells in the human penis. AIDS. 2006 Jul 13;20(11):1491-5.
  2. Auvert B, Taljaard D, Lagarde E 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.
  3. Bailey RC, Moses S, Parker CB 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.
  4. Gray RH, Kigozi G, Serwadda D et al. Male circumcision for HIV prevention in men in Rakai, Uganda: a randomised trial. Lancet. 2007 Feb 24;369(9562):657-66.
  5. Millett GA, Flores SA, Marks G et al. Circumcision status and risk of HIV and sexually transmitted infections among men who have sex with men: a meta-analysis. JAMA. 2008 Oct 8;300(14):1674-84.
  6. Jin F, Jansson J, Law M, et al. Per-contact probability of HIV transmission in homosexual men in Sydney in the era of HAART. AIDS. 2010 Mar 27;24(6):907-13.
  7. Templeton DJ, Millett GA, Grulich AE. Male circumcision to reduce the risk of HIV and sexually transmitted infections among men who have sex with men. Current Opinion in Infectious Diseases. 2010 Feb;23(1):45-52.
  8. Wiysonge CS, Kongnyuy EJ, Shey M et al. Male circumcision for prevention of homosexual acquisition of HIV in men. Cochrane Database of Systematic Reviews. 2011;6:CD007496.


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