It's good that you've asked. If only more people had a bit of curiosity.
I am not medically qualified in any way, so I would generally refer to reputable medical websites. In the UK the NHS (forget the crap you've been hearing about our National Health Service in the USA recently) run
this site which states
Quote:"HIV is spread through the exchange of bodily fluids. This most commonly happens during sexual intercourse, including oral and anal sex. HIV can also be transmitted through sharing needles, or from a pregnant woman to her unborn baby."
From what I have read in several places evidence for the transmission of HIV through oral sex has been subject to debate, but it seems there is a small chance. This chance obviously increases if you have cuts, abrasions, a sore throat or mouth ulcers. I have heard it said that small abrasions can be caused by over vigorous teeth-brushing, so if you go on a date and you think oral sex might be an option use mouthwash instead. Whatever you do, sex is a matter of managing risk (as well as jolly good fun, of course!). If you are going to act in a totally risk averse way you avoid sex altogether or you use a condom or some other kind of barrier to stop fluid from your partner getting into your mouth. In practice I am not sure that many men actually go this far. I don't think I have ever met anyone who did. While there is the possibility of the virus being present in pre-cum of an infected person it is safer to avoid him ejaculating into your mouth. Again, you weigh up the risks and take your chances. If you can trust your partner you can discuss the degree of potential risk through previous sexual activity and come to some more informed decisions.
I reality, while HIV/AIDS is the scary one (and many people on here will have tales of loved ones who have been lost to this virus) other diseases are far more easily transmitted during oral sex. This fact seems not to be repeated often enough. If you are sexually active and having sex with other men you should at least see about getting vaccinated against hepatitis B. I don't know how you would go about this in the USA, but in the UK we can just go to a clinic and make the arrangements. Our health service means that no money changes hands and you don't even have to give your real name or address. I was still in the closet and used obviously false details with no problem when I had a hep B course of vaccinations a few years ago.
This page on the THT website give the following advice on oral sex:
Quote:"Can HIV be transmitted through oral sex?
The short answer is yes. But the risk is lower than some other sexual activities.
Recent surveys have shown that only a small minority of new cases of HIV that are diagnosed are due to oral sex. Although HIV is present in vaginal fluids, semen and the clear fluid that your penis produces for lubrication before orgasm, it is unlikely these will come into contact with your bloodstream during oral sex. But while it’s unlikely, it’s not impossible.
The risk factor is largely due to your oral hygiene. If you have ulcers, dental bleeding or lacerations then theoretically the infection could reach your bloodstream. However, saliva has enzymes that inhibit transmission and the cells in the mouth aren’t very absorbent, so the chance of transmission is low.
Ways to lower the risk
If you’re performing oral sex on a man then you could:
avoid getting semen in your mouth
use a condom
have oral sex with fewer men.
look after your oral hygiene.
Do not have oral sex when you have a throat infection or have bleeding gums.
If you’re performing oral sex on a woman then you could:
use a barrier such as cling-film, a dental dam, a Femidom or a sheet cut from a condom
have oral sex with fewer women
look after your oral hygiene.
You should avoid oral sex when a woman is having her period.
Other infections
There are other sexually transmitted infections that are transmitted much more easily by oral sex. Herpes, Syphilis and Gonorrhoea can all be transmitted in this way, so it is worth looking at your oral sex practices as part of a healthy sex life."
The way things stand at the moment, and for the foreseeable future, AIDS is still an incurable and life-threatening disease. You only have to catch it once. Sure we have come a long way in finding drug combinations to manage the symptoms, but these treatments can also have some very unpleasant side effects.