Since the 1930s and the work of Hale and Warkany on birth defects produced by variations in dietary vitamin A, it has been recognised that the developing fetus is particularly vulnerable to adverse influences in the environment. . Studies of malformations at birth remained largely in the hands of paediatricians who, for instance, quickly established the con- nection between rubella infection in early pregnancy and the birth of severely affected infants. However, it was through the tragic events of 1962, when dramatic increases in the incidence of phocomelia in newborn infants in Germany, the...