© Jan Banning / Panos Pictures..Between 1961 and 1971, US troops sprayed 72 million litres of herbicides over ± 10% of the surface of South Vietnam - 51 million of this was Agent Orange, containing a total of 170 kilos of 2,3,7,8-T4CDD (dioxin)..Laboratory tests led to the conclusion that dioxin can lead to birth defects and genetic damage in animals. Vietnamese and other researchers found higher rates of congenitally malformed babies among people who have been sprayed with this defoliant..Cam Lo district (Quang Tri province) just south of the former North-South border is one of the heavily sprayed areas. .Nguyen Duy Khan (boy, 20!), here with mother (Phan Thi Nghia, 43) and father Nguyen Tuan (46), is a possible victim. The mother: "Khanh can hear, and stand up and walk a little, but only with support. He can understand a little bit, but he can't speak except for the word 'mother'. He doesn't feel pain, cold or heat. He can sometimes eat by himself. Khanh doesn't control his urination and defecation. He is now 20 years old, but looks like a child of 6"..The parents are farmers and live in Cam Hieu commune (Cam Lo).