The young were once considered relatively safe from HIV/AIDS. Today, more than half of all new infections strike people under the age of 25. Girls are hit harder and younger than boys. Infant and child death rates have risen sharply, and 14 million children are now orphans because of the disease. The world's two billion children and adolescents are at the center of the HIV/AIDS crisis. And yet they are the ones who offer the greatest hope for defeating the epidemic.