Gay men on the pill.

After 20 years, why don't we have a treatment that could help prevent you from getting HIV?

I'm not talking about a vaccine, which most scientists consider a pipe dream against a diverse and constantly mutating retrovirus like HIV.

I'm talking about some kind of drug that HIV-negative men could use to lower their risk of getting the mother of all cooties in the first place. Many young HIV-negative men can feel somewhat helpless in the face of a lifetime of sexual activity in which the chances of getting HIV are considerable--even if they do their best to practice safer sex all the time.

Yes, condoms are the first defense and should continue to be. But they're fallible. And oral sex isn't fail-safe. In fact, any sexual encounter with a pozzie always contains some risk of transmission--however small. The fear and tension within relationships where one man is negative and the other positive is profound and constant. And the number of these relationships is growing as more and more HIV-positive men live long and fulfilling lives. Is there anything we can do to make the situation better?

The answer is: possibly. And we've been far too passive in pursuing the opportunity. A large study among Cambodian women, partially funded by the Gates Foundation, was to test whether daily doses of Viread, Gilead Science's anti-HIV medicine, could reduce HIV transmission among HIV-negative sex workers. The idea was that if you already have antiretroviral drugs in your bloodstream, the vitals has a far harder task of infecting you. A small study of monkeys had found that Viread did indeed help prevent transmission of the simian version of HIV. ACT UP protested the human study on ethical grounds (they demanded 30 years' health insurance for the subjects), and the Cambodian government shut it down in August, but no one has disputed the basic logic of the study. Think of it as doctors now think of a major HIV meds blast after you have a risky encounter and fear you might have become infected. But in this case the drug is taken before any encounter--and adds to the odds of staying negative.

What's not to like? Well, side effects, of course. Viread can cause nausea, diarrhea, vomiting, and gas--but compared to the burden of the more hefty drug regimens that HIV-positive men endure, it's a no-brainer. The expense? Sure. But compared to the possible expense of full-blown HIV regimens, it's a bargain. No, the real reason this approach has been discouraged in the United States is the condescending fear that gay men who believe they are more immune to HIV will adjust their behavior accordingly and so make themselves even more likely to get HIV. "Hey, I'm on the pill," you can hear Viread-protected men say. "You don't have to put on a rubber."

So what? That's happening anyway, as HIV becomes much less scary to many more men. At least with Viread there's a chance HIV won't be so easily transmitted. And in any case, the only way to tell whether this will actually be the case is to conduct a study, instead of asking third-world women to be the guinea pigs, why can't American gay men demand a big study for themselves? HIV-negative men in serodiscordant relationships may be particularly interested. If we can thereby reduce transmission even by a notch, we can have a big impact on the epidemic--just as the use of antivirals among HIV-positive men has cut rates of transmission from where they might otherwise be.

Sex, after all, is not our enemy. HIV is. If we can make our sex lives safer by taking HIV meds before we get infected, we might raise the chances of never getting infected at all--and have less fearful and more rewarding sex as a result. Every gay man has an interest is seeing whether that might be tree. But right now, we don't even know the data--because no studies are being conducted in the United States. After nearly 25 years of AIDS, that's not good enough. And HIV-negative men need to demand better.