CONGENITAL anomalies present one of the major problems in pediatrics at the present time. Fifty years ago communicable disease was the principle cause of morbidity and mortality in childhood. Now all this has changed, and, in many countries with well developed health services, the infant mortality has declined to very low levels due largely to specific control measures directed against the infectious diseases, but there has been no such decline in the incidence of congenital anomalies. In Great Britain, for example, the incidence of major malfor mations detectable at birth is 17.5 per 1,000 total births and, at the age of 5 years, has risen to 23.2 per 1,000 births. Furthermore, 20% of all infant deaths result from congenital malformations, and the same high incidence occurs in the United States.1 Little is known about causation of congenital anomalies. Approximately 20% can be ascribed to some genetic or environmental factor,