Characteristics of parents of Down's children and control children with respect to factors present before conception.

A study of the characteristics before conception of 145 mothers and 135 fathers of Down's children compared to control parents has shown that the Down's mothers, even when controlled for age, had significantly more illnesses before conception, particularly psychological illness, and significantly more drug ingestion in the year before conception. There were no other differences in the mothers and the fathers did not demonstrate a similar tendency. Since morbidity and drug ingestion are both associated with increasing age, it is suggested that further investigation of the role of environmental factors such as illness or drug ingestion may elucidate further the aetiology of Down's syndrome.