On the outskirts of Abuja, Nigeria, in a dirt-floor building that serves as an HIV-training center by day and a bar by night, a group of sex workers welcomed their visitors: former U.S. president Jimmy Carter and Bill Gates, Sr., father of the world's richest man. Representing the Carter Foundation and the Bill and Melinda Gates Foundation, the two seniors stopped in during a whirlwind tour of three AIDS-ravaged African nations.

One woman -- dubbed "Angela" in the duo's on-the-road e-journal (see www.slate.com) -- told her story: "I got married at 15 to a man who beat me. I left him and had nowhere to go. I came into sex work to support myself." Now Angela's a peer educator, training other Nigerian prostitutes (one-third have HIV) to protect themselves and clients by insisting on condom use. Far from being scandalized, Sunday-school teacher Carter wrote, "Most see commercial sex workers as a problem in the spread of the epidemic. The women we met today see themselves as part of the solution. And they are right."

Carter and Gates got a chillier reception from South Africa's ruling African National Congress (ANC). After their visit -- along with former South African president Nelson Mandela -- to a clinic where pregnant, HIV positive women get nevirapine to prevent mother-to-child transmission, the pair pressured President Thabo Mbeki to expand access to the drug. The ANC fired back with a statement accusing Carter of being "willing to treat our people as guinea pigs."