China's Lost Girls

National Geographic Ultimate Explorer host Lisa Ling examines the consequences of China's two-decade-old, ''one-child policy'' designed to curb the country's exploding population. Due to cultural, social and economic factors, traditional preference leans toward boys, so girls are often hidden, aborted, or abandoned. As a result, tens of thousands of girls end up in orphanages across China.

Today, more than one quarter of all babies adopted from abroad by American families come from China