Globally, the HIV/AIDS infection is spreading most rapidly among young people between the ages of 15 and 24. Half of new infections worldwide, affecting 5,000 to 6,000 youth each day, occur in this age group. Women and girls now comprise 48 percent, or 17.7 million, of the nearly 40 million people living with HIV/AIDS. Especially vulnerable are young women and girls, who make up 75 percent of all new cases in sub-Saharan Africa, and a growing proportion of those infected in Asia, Eastern Europe and Latin America. Three-quarters of all women and girls with HIV and AIDS live in sub-Saharan Africa, many of them in the countries where the President’s Emergency Plan for AIDS Relief (PEPFAR)4 is working. In that region, young women and girls are at least three times more likely to be infected than their male cohorts.