Dear Dr. Hunter: Thank you for a great and very informative site. I am male, and my questions relate to an explanation of the risk assessments you frequently give re: risk to a male in heterosexual acts with a woman.
1) I understand that you say a male performing oral sex on a woman (cunnilingus) is extremely tiny even if she did have HIV, like 1 in 10,000 or the like, and even that you are not aware of such a case ever having been documented, correct? My question is – could you explain medically/biologically why it is so unlikely for a male to contract HIV through cunnilingus, what is it about the disease that makes this so highly unlikely? If you don’t want to answer this, can you possibly point me to some site(s) that might explain why cunnilingus is so low-risk for the man? Again, from the medical/biological perspective, what is it about the HIV virus that makes this so?
2) Likewise, you say that for a man to catch HIV with unprotected vaginal intercourse with a woman one time, even if she were HIV positive, is like 1 in 1,000 (or 1 in 2,000?). Again, medically, what is it about the disease that makes this so rare? Also, just curious, where do these numbers come from? Again, from the medical/biological perspective, what is it about the HIV virus that makes this so?
3) Finally, why is it that I am reading so much on the internet that makes it seem like these heterosexual acts are in fact very high-risk activities? For example, I read one forum where a man asked about cunnilingus, and some nurse told him that the woman’s vaginal secretions were “highly infectious” and that he should go get tested. I ask because it seems like most (or at least many) of us guys on this site are here due to freaking out about one or two incidents (“the condom came off with the CSW,” “unprotected sex with girl I just met” etc. etc.).