Back on the first season of Sex and the City, good girl Charlotte confided in her gal pals that her new boyfriend wanted anal sex. So given the show’s tendency to both make and mimic trends, HIV preventionistas who think they have to broach that taboo topic only with gay men should think again.

According to a comprehensive report by former University of California/San Francisco researcher Daniel Halperin, PhD, straight women are getting rear-end action in droves. This spells trouble for a population that is least likely to use condoms (because there is no fear of pregnancy) for the most dangerous activity (anal sex).

In the U.S., surveys show that about 20 to 30 percent of het gals have let their men in the back door, about a third on a regular basis. And for reasons ranging from contraception to kinkiness, the practice is reportedly even more common among those who engage in high-risk behaviors—sex workers, adolescents, serodiverse couples and ladies who lunch with bi men or IV drug users.

This means that, numerically, more American women are having unprotected receptive anal intercourse than gay men (though rates of infection are, of course, much lower). Given that HIV is believed to be 10 times more transmissible through unsafe anal sex than vaginal sex, a significant number of newly infected women can blame it on butt-banging.“I think prevention as a whole needs to refocus on anal sex,” said Halperin of what he sees as an ironic return to AIDS’ early days, when phobic hets squirmed at the spotlight thrown on what homos do in bed.

“The whole panorama of sexual acts needs to be addressed by prevention,” said Deb McSmith, ED of Women Organized to Respond to Life-Threatening Disease. “It just speaks to the depth of our discomfort about sex that it’s not there already.” Prevention workers had better get comfy fast—before anyone else ends up in deep shit.