"You pays your money," I said as we discussed taking the occasional foray into un-safer sex, "and you takes your chances." But chances at what, one asks? What are we even protecting ourselves from, with all this dickering and negotiating and insisting?

Is HIV even a reasonable worry for my friends, or myself, or for you, dear readers who are pretty much indistinguishable, demographically, from us? The answer, as it turns out, is no, but that is not, of course, the end of the story.

The AIDS epidemic I was taught to expect and fear when I was first training to be a sex educator, the one where "everyone's equally at risk," never did arrive, not in the developed West, anyway. The epidemiology here is simply different from that of Sub-Saharan Africa, where AIDS has produced the sort of apocalyptic devastation people used to write novels about when that sort of speculation might still be considered entertainment and not mere grim reportage.

Here, it's another story. If you remember those articles about how a woman over 35 is more likely to be taken hostage by terrorists than marry over the age of 35 (Ha! I did it! In your face, terrorists!), and add in your chances of being hit by lightning anywhere other than a trailer park or a golf course, that's about your chance of contracting HIV while having unprotected vaginal sex with middle-class, non-injection-drug-using, probably recently divorced straight people in this country.

It's just not going to happen. Which is not to say you ought to be partying without a balloon. I may have emerged from singledom unscathed but I'm actually freakishly lucky that way. Minna got herpes, and she was no more reckless than I was. My friend Yvette got everything except HIV and Hep C, to the point where she offered, when asked to speak on a panel about STDs [sexually transmitted diseases] as part of a sex ed class, to sit in each of the chairs in sequence and save the organizers time and effort.

About one in five Americans over the age of 12 has genital herpes, whether they know it or not (herpes can hide so effectively that it's possible to spread it without ever knowing you have it). Herpes infections can range from barely an issue to nearly unbearable, and even the hardly noticeable kind carries serious social repercussions, forever.

HPV [human papilloma virus] is even more common and a lot scarier, since it causes not merely social awkwardness but cervical cancer. The old classics, gonorrhea and syphilis, are still around and the clap, at least, is making serious strides toward its goal of becoming antibiotic resistant.

A case of chlamydia comes free with a college education these days. None of this is fun and some of it is deadly serious, and I absolutely think you ought to be careful (whether this entails partner choice, barriers, or, most likely, some combination of both) if you're sexually active. (That phrase always puts me in mind of monkeys for some reason, swinging through the trees, throwing poo, and being "sexually active," but I realize that is my problem, not yours).

I want you to be careful. I just don't want you to waste too much time fretting about AIDS while you're doing it. You'd be better off fretting about MRSA (methicillin-resistant staphylococcus aureus), the drug-resistant infection one gets in hospitals, which is out of control) and watching out for HPV and herpes. And terrorists. And lightning.