Agent Orange was a combination of two defoliants, 2-4-5-T and 2-4-D, contaminated by Dioxin (TCDD), a toxic by-product of the chemical production process. Over 19 million gallons of herbicides were sprayed in Vietnam between 1962 - 1971 to destroy crops and ground cover. The current scientific evidence argues not only that dioxin is a potent carcinogen, but that it appears to have more profound non-cancer health and environmental hazard effects that include reproductive, developmental and immunological effects. Dioxin appears to act like a persistent synthetic hormone interfering with important physiological signaling systems that can lead to altered cell development, differentiation and regulation. This National Birth Defects Registry report shows the differences in structural and functional birth defects in 1457 children of Vietnam veterans compared to 3131 children of non-veterans in the registry.