MSM (Men who have Sex with Men)

"Men who have Sex with Men" — a behavioral term used in public health and research to describe men who have sex with men, regardless of how they identify. MSM includes gay men, bisexual men, and men who may identify as straight but have sex with men.

MSM is used in health contexts because risk (of HIV, STIs) follows behavior, not identity. A man who has sex with men but identifies as straight is still at risk and still needs sexual health services — which is why clinics, PrEP programs, and HIV research use the term.

MSM is a descriptive category, not an identity. Most people who are MSM identify as gay, bi, or queer in daily life. The term exists alongside MSW (men who have sex with women) and WSW (women who have sex with women).