Well, I have to take Steve's "logic" to task. He says:
HIV is not passed on by promiscuity. It is passed on by someone who has it to someone who hasn't.

Trouble is, Steve, the more sex partners you have, the better chance you have of coming across one who has HIV.
If you and your mate have a lifelong relationship and you don't have other sex partners, your chance of getting a sexually transmitted disease is slim to none. Sexual fidelity does help control the spread of disease. So do condoms. To deny the efficacy of either, is equally silly.

Actually, Joe, it was someone else who claimed the logic for me. I stated an incontrovertible fact, that's all. Right,so in a world in which people went around blithely and blindly having unprotected sex with all and sundry, your argument applies. But underlying what I said is that it does not have to be that way. You can have sex with lots of different people and always insist on condoms. You can have sex with lots of different people and avoid the riskiest sexual practices. You can have sex with lots of different people after you've known them for a while and checked them out. You could be having sex in an area where there is no HIV (like we all were half a century ago). Your correlation under any of these circumstances founders at least somewhat if not almost completely. What my four scenarios have in common is education. I've said it many times in other contexts (such as how we can cut the numbers of unwanted pregnancies and therefore abortions): the answer, or at least a very big part of it, is education. Good education for sex, relationships and self-respect. And the removal of faux-moral barriers to using condoms, of course. What we pejoratively and moralisingly refer to as promiscuous behaviour (and I note that you snook that moral buzzword "fidelity" in there) may be the norm in many countries and in certain communities in other countries. You will not change that behaviour (and who's to say it's wrong anyway? Western values??) by moralising at people and hectoring them about how they're promoting HIV. That just has that horrid, evangelical, opportunistic Christian stench about it. The Catholic Church has serially demonstrated that you don't change behaviour by moralising at people. What did the Church ever do to cut abortion rates! What we need is education, education, education.