Men who have sex with men

Men who have sex with men or males who have sex with males (MSM) refers to men who engage in sexual activity with other men, whether they identify as gay, bisexual, or neither. This term was defined in the 1990s by epidemiologists in order to study the spread of disease among any and all biological males who have sex with other biological males. The term is intended to reference a particular category of males who are at higher risk for sexually-transmitted diseases such as HIV. MSM is considered a behavioral category, not any kind of identity. Its primary use is in terms of studying the spread of the HIV virus.

MSM as behavioral category
Young and Meyer (2005) note that the term has been in use within the public health discourse since 1990 or earlier, but that the coining of the initialism by Glick et al. (1994) "signaled the crystallization of a new concept." They trace the emergence of this behavioural concept to two very distinct academic perspectives. First, it was pursued by epidemiologists seeking behavioral categories that would offer better analytical concepts for the study of disease risk than identity-based categories (such as "gay", "lesbian", or "straight", because a man who self-identifies as gay or bisexual is not necessarily sexually active with men). Second, its usage could in part be explained by the criticism of sexual identity terms prevalent in the "social construction" literature, which typically rejected the use of identity-based concepts across different cultural and historical contexts.

MSM as a construct
As a risk category, MSM are not limited to small self-identified and visible sub-populations, such as gay men and male sex workers. MSM and homosexual refer to different things: behaviors and social identities. MSM refers to sexual relationships between men, whether or not they identify as homosexual or bisexual. Homosexual orientation refers to sexual/romantic attraction between men and does not necessarily imply any history of sexual relationships. Homosexuality refers to more than the sexual relationship and may extend to broader relationships with the same sex. Its precise use and definition has varied with regard to transwomen. Some sources consider transwomen to be MSM, others considering transwomen "along side" MSM, and others are internally inconsistent (defining transgender women to be MSM in one place but referring to "MSM and transgender" in another).

In their assessment of the knowledge about the sexual networks and behaviors of men who have sex with men in Asia, Dowsett, Grierson and McNally concluded that the category of MSM does not correspond to a single social identity in any of the countries they studied.

"'The literature reveals that there are no socially or self-defined groups of men that fit into an overarching category of MSM. What the review shows is that there are just men!! Fishermen, students, factory workers, military recruits, truck drivers, and men who sell sex, and so on: all these categories of men are to be found in the studies and programmes reviewed.'"

There were no similar traits in all of the MSM population studied, other than them being males and engaging in sex with other men.

Health issues
Men who have sex with men are more likely to get HIV in the modern West, Japan, India, and Taiwan, as well as other developed countries than among the general population. In the U.S., their HIV prevalence is 60 times higher than the general population. An estimated 62% of adult and adolescent American males living with HIV/AIDS got it through sexual contact with other men. This compares to an estimated 13% of American males who get HIV from sexual contact with a female who is known to have, or is at high risk for, HIV infection.

Infection with the Hepatitis B virus is about 5-6 times more common, and Hepatitis C virus infections are about 2 times more common, in men who have sex with men than in the general population. They also have an increased incidence and prevalence of Kaposi's sarcoma-associated herpesvirus, which causes a cancer called Kaposi's sarcoma in immunocompromised individuals. In 2006, 64% of the reported syphilis cases in the United States were among men who have sex with men. Men who have sex with men are 17 times more likely to develop anal cancer than heterosexual men, probably due to a higher risk of human papillomavirus. Many people become infected with HPV soon after becoming sexually active.

MSM also have high rates of intestinal parasitism throughout the world.

Growth rate
HIV infection is increasing at a rate of 12 percent annually among 13-to-24-year-old American men who have sex with men. During the last 10 years, syphilis outbreaks among men who have sex with men have been recorded in countries across Europe. This follows the general increase in STDs among men who have sex with men. This increase in cases among young Western males may have to do with the new generation being relaxed because of new treatments and being not personally affected by the initial AIDS breakout in the 80s. In developing countries, HIV infection rates are skyrocketing among men who have sex with men.

Explanations
One reason for higher prevalence is that engaging in receptive anal intercourse carries a higher risk of transmitting STDs than other forms of penetrative sex, and, according to one study's abstract, can be an important risk factor for intestinal parasitism, although another study found no correlation between "detection of E. histolytica [the parasite which causes amoebiasis] and sexual practices". Anal sex is more common in homosexual sex than in heterosexual sex. The prevalence of anal sex among homosexual couples in the West has varied over time. Magnus Hirschfeld, in his 1914 work The Homosexuality of Men and Women, reports the rate of anal sex among homosexual men surveyed to be 8%, the least favored of all the practices documented.

By the 1950s in the United Kingdom, it was thought that about fifteen percent of male homosexuals practiced the method. The Gay Urban Men's Study (P.I. Stall, UCSF) and the Young Men's Study (YMS, PI Osmond/Catania, UCSF) indicate that 50% of men surveyed engage in anal sex. The Laumann study claims that 80% of gay men practice it.

A survey conducted from 1994 to 1997 in San Francisco by the Stop AIDS Project indicated that, over the course of the study, the proportion of men who have sex with men engaging in anal sex increased from 57.6% to 61.2%.

A comparison study of HIV-infected men found that those who had sex with men were especially unlikely to receive HIV preventative services even though they were more likely to report unprotected sexual intercourse with seronegative and unknown serostatus casual partners. This can lead to the rapid transmission of HIV among small clusters of gay men.

A 1990 study called The Social Organization of Sexuality showed that men who had at least one male sexual partner in the previous 5 years had an average of 16.7 sexual partners during that time period, while men who only had sex with women had an average of 4.8 sexual partners during that time.

One study based on the Amsterdam Cohort Study (which includes only MSM who have had two sexual partners in the previous six months) concluded that young MSM were more likely to have contracted HIV from a steady partner than from a casual partner, compared with older MSM, possibly due to higher rates of unprotected anal intercourse.

However, the persistence of disparities in HIV between heterosexual individuals and MSM in the United States cannot be explained solely by differences in risky sexual behavior between these two populations; it is also contributed to by both the lack of "sexual role segregation" between male sex partners and "the differential anal/vaginal transmission probabilities".

James Chin, clinical professor of epidemiology at UC Berkeley, has charged that political correctness has led to the under-targeting of those at greatest risk of acquiring HIV (including MSM) in HIV/AIDS prevention programs.

In developing countries, homosexual relationships may be illegal, making MSM difficult to reach. Studies have found that less than 5 percent of MSM in Africa, Asia, and Latin America have access to HIV-related health care.