Wish I had the link, but I read a CDC report that said soon 50% of homosexuals would have HIV.
other articles/stats
http://www.cdc.gov/hiv/statistics/basics/ataglance.html
http://www.cdc.gov/hiv/group/age/youth/
CDC: 20% of Gay Men Are HIV-Positive, but Nearly Half Dont Know It http://healthland.time.com/2010/09/26/study-20-of-homosexual-men-are-hiv-positive-but-only-half-know-it/