You people amaze me, how can you argue and debate when you have not a clue what you are debating about?
MSM is a registered demographic in all of the health agencies.
It stands for "Men who have sex with men", basically male homosexuals.
They make up 2% of the population, but account for 80% of all new HIV infections in men and 75% of all syphilis infections in men and women.
They are also over represented in all other STDs.