It’s interesting that epidemiologists were forced to make this distinction/realization, however, in the interest of scientific accuracy, because not all gay men have (anal) sex with men and not all men who have sex with men identify as gay (i.e. some identify as straight, are in stable hetero relationships, and do it as an anonymous thing and never have relationships with men). Thus the term MSM (Men who have Sex with Men) was born:

http://en.wikipedia.org/wiki/Men_who_have_sex_with_men

That’s a surprisingly good wikipedia article, by the way, and it mentions some of the same things this post is getting at, under “MSM as a constructed behavioral category”.

Thanks.