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Josef Warkany studied the environmental causes of birth defects in the United States in the twentieth century. Warkany was one of the first researchers to show that factors in the environment could cause birth defects, and he helped to develop guidelines for the field of

In 1984, J. David Erickson and his research team published the results of a study titled "Vietnam Veterans' Risks for Fathering Babies with Birth Defects" that indicated that Vietnam veterans were at increased risk of fathering infants with serious congenital

Sidney Q. Cohlan studied birth defects in the US during the twentieth century. Cohlan helped to discover that if a pregnant woman ate too much vitamin A her fetus faced a higher than normal risk of teratogenic effects, such as cleft palate. A teratogen is a

Spina bifida is a birth defect that affects the spines of developing fetuses and infants, and research in the 20th century indicated that chemicals in the herbicide Agent Orange likely led to the birth defect. People with spina bifida can have nerve damage, paralysis, and mental disabilities. During the Vietnam War in the 1960s, the US military employed Agent Orange and other herbicides to

Editor's Note: This article replaces the previous article on this topic, which was published in this encyclopedia in 2012. The 2012 article may be found at http://hdl.handle.net/10776/4202.