Tran Duc Nghia, 39, watches from a wheelchair as his mother is interviewed by a television news crew at the family's home in Da Nang, Vietnam. Nghia and his younger sister are second-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. According to his mother, Nghia was born normally, but began developing problems by the time he was 12. He is now completely disabled, both mentally and physically, and his sister is beginning to exhibit many of the same symptoms. The family gets no government support, and Hoang Thi Te, 75, the mother, worries who will take care of her children when she is gone. March 18, 2013.