Appearance of skeletal abnormalities in the offspring of rats on a deficient diet.

Warkany was the first to prove that congenital developmental disorders can be induced by exogenous factors in mammals. His studies led to the definition of both genetic and environmentally induced structural defects. See also: Warkany, J. "Effect of maternal rachitogenic diet on skeletal development of young rat," Amer J Dis Child., 66 (1943) 511.