Unless you have unprotected sex with them, there is no danger.
I'm sure that you understand how vaccination works as a public health benefit. Well homosexuals are walking disease factories and even if you don't have sex with a homosexual you're still facing downstream risks from having sex with someone who, somewhere up the line, had sex with a homosexual.
From the
Centers for Disease Control:
The data, presented at CDC's 2010 National STD Prevention Conference, finds that the rate of new HIV diagnoses among men who have sex with men (MSM) is more than 44 times that of other men and more than 40 times that of women.
The range was 522-989 cases of new HIV diagnoses per 100,000 MSM vs. 12 per 100,000 other men and 13 per 100,000 women.
The rate of primary and secondary syphilis among MSM is more than 46 times that of other men and more than 71 times that of women, the analysis says. The range was 91-173 cases per 100,000 MSM vs. 2 per 100,000 other men and 1 per 100,000 women.
Or
this:
Health officials this week announced a cluster of cases of invasive meningococcal disease that sickened eight people in the LA area. Among those who fell ill, half were gay or bisexual, including the three who died. Two of the victims were HIV-positive.
Or
this:
Health officials are tracking a new type of infection with Staphylococcus aureus that is resistant to even more antibiotics than MRSA, the drug-resistant staph that has spread from coast to coast over the past seven years. (MRSA stands for "methicillin-resistant Staphylococcus aureus".)
So far, nearly all recognized cases of the multiply drug resistant staph have been among gay and bisexual men. The cases are showing up most often in San Francisco, Los Angeles and New York.
The problem with walking disease factories is that the diseases that they're incubating have a way of spreading to the general population and you don't need to have sex with homosexuals in order to be infected, just proximity is sufficient for some diseases.