For 20 years, women convinced they got HIV from sex with a woman have lacked scientific proof that it could happen —until now, according to January’s Clinical Infectious Diseases. The journal reported the case of HIV in a woman who claimed to have had sex for the past two years only with her HIV positive girlfriend. Not an impossibility, but for once researcher Helena Kwakwa, MD, had a smoking gun: Lab analysis showed a genetic match between the two ladies’ HIV.

Eureka! But how did transmission occur if women have only small concentrations of virus in their vaginal secretions? The gals reported that they never had sex during their periods, and the newly positive woman professed zero history with injection drugs or sex with men. Kwakwa’s deduction? Fresh blood on shared sex toys.

The study was sweet satisfaction for Amber Hollibaugh, founder of the Lesbian AIDSProject at New York City’s GMHC. “Women who sleep with women knew damn well that the way they’d been infected was by a female partner,” she said. “But no one in AIDS research was dealing with it.”Not dealing or not discovering? According to a CDC fact sheet (www.cdc.gov/hiv/pubs/facts/wsw.htm), a study of more than 1 million female blood donors found no HIV among those who reported lesbian sex as their sole risk. But the CDC also notes that girl-to-girl transmission, though rare, may be masked by such cofactors as those ruled out in Kwakwa’s case. And this reminds health pros to check their assumptions about lesbians’ risk for HIV—and that dykes may want to dental-dam it.

So what can Sapphic sisters take away from the case of this headline-maker? “The risk is low, but it’s there,” Kwakwa said. “I see women who would not be coming in with HIV if they’d had the proper information and recognition of risk.” Hallelujah, said Hollibaugh: “People think lesbians have vanilla sex—we hold hands, we take long walks, we’re not kinky,” she said. “If that’s what you think about lesbians, you’re not going to assume they do anything that would put themselves at risk.”