Tran Thi Hoa, 47, points to a baby photograph of her 21-year-old son La Thanh Toan, who sits below it, at their home near Da Nang, Vietnam. The photograph was taken when Toan was 4-years old, and shows him as a normal child. But he and his brother Nghia, now 18, 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. They are now confined at home as their bodies and lives waste away. Jan. 5, 2013.