For some further reading:
http://www.porn-free.org/pdf/Gay_Sex_Health_Risks.pdf
http://www.missionamerica.com/homosexual.php?articlenum=16
An excerpt from the second link:
The list of medical diseases found with extraordinary frequency among male homosexual practitioners as a result of abnormal homosexual behavior is alarming: anal cancer, chlamydia trachomatis, cryptosporidium, giardia lamblia, herpes simplex virus, human immunodeficiency virus or HIV, human papilloma virus -- HPV or genital warts -- isospora belli, microsporidia, gonorrhea, viral hepatitis types B and C, and syphilis.
Sexual transmission of some of these diseases is so rare in the exclusively heterosexual population as to be virtually unknown. Others, while found among heterosexual and homosexual practitioners, are clearly predominated by those involved in homosexual activity.
Men who have sex with men account for the lion's share of the increasing number of cases in America of sexually transmitted infections that are not generally spread through sexual contact.
These diseases, with consequences that range from severe and even life-threatening to mere annoyances, include hepatitis A, giardia lamblia, entamoeba histolytica, Epstein-Barr virus, neisseria meningitides, shigellosis, salmonellosis, pediculosis, scabies and campylobacter.
The risk of diseases is NOT the same for heterosexuals as it is for homosexuals . The first article I linked to goes into some almost graphic (although in medical terms) detail about why this is the case. Basically, it boils down to the fact that human bodies were not designed for homosexual behavior. It is not natural, it is harmful.