The Pill got a dose of bad press as research in the Lancet suggested a link between oral contraceptives and HIV transmission. A Kenya study of 318 HIV positive women revealed that hormonal contraceptives and vitamin A deficiency affect the shedding of HIV cells into body secretions. The stats, though preliminary, may point to an important determinant of sexual and vertical transmission of HIV, said lead researcher Dr. Sara Mostad, of the University of Washington, Seattle. “If you're on the Pill, there's a possibility you're more likely to transmit HIV.” But she warned against overestimating the finding: “Birth control pills are a fabulous form of contraception and it would be too bad to incriminate them at an early stage.” Besides, she said, condom use should be a given.

Related studies suggest that hormone intake may also cause a thinning in the membranes lining the vagina and cervix. The thinner the lining, the easier it tears, making the woman more vulnerable not only to giving but to getting HIV