Kristen Vetter, a nurse and daughter of U.S. war veteran Larry Vetter, conducts physical therapy with La Thanh Toan, 21, at his home near Da Nang, Vietnam. Toan and his 18-year-old brother Nghia are third generation victims of dioxin exposure, the result of the U.S. military's use of Agent Orange and other herbicides during the Vietnam War more than 40 years ago. The brothers were born healthy but began to suffer from muscular dystrophy and other problems as they grew older. Now they are confined at home as their bodies and lives waste away. Jan. 5, 2013.