In 2001, a group of scholars at University of California, San Francisco came up with a scheme that they hoped would protect African women from HIV. They had been working in Zimbabwe, a poor, politically troubled nation in Southern Africa, where the epidemic had killed more than a million people over two decades. Virtually everyone in Zimbabwe was aware of AIDS. The country had been exposed to anti-AIDS media campaigns since the 1980s and a school-based AIDS education program since 1994. Nevertheless, by 2001, around a quarter of all Zimbabwean adults were infected with HIV, and the virus was spreading rapidly, especially among teenage girls. It was urgent for researchers like them to come up with a solution.