Thus, even with a condom, anal sex can be risky. Retrieved August 17, Men who have sex with men may donate blood; No deferral, except for blood transfusions. Though not commonly classified as an STI, giardiasis can be transmitted between gay men,  and it can be responsible for severe weight loss and death for individuals who have compromised immune systems, especially HIV. Much literature on mental health and homosexuals centered on examples of their depression, substance abuseand suicide. Men who have sex with men may not a man having sex witha man blood; Permanent deferral.