Tran Duc Nghia, 39, sits in a wheelchair in his 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 physically and mentally disabled, and his sister is beginning to exhibit many of the same conditions. 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. She is bitter at the U.S. government for using toxic herbicides during the war, and says she wishes the U.S. military would have killed her children right away, instead of leaving to suffer decades later. "I am very angry. They are heartless people," she says of U.S. policymakers. "They are the cause of this illness for my children. I've had to care for him for almost 40 years. I feel like I've been in prison." March 18, 2013.