Comment

Abstract

The organizers of the conference have been kind enough to invite me to make some comments, so I thought I would supplement what Dr Jans has said using illustrations from research on animals. The vast majority of these studies on humans have been retrospective in nature and, although provocative, are limited by the problems entailed in such methodologies. Dr Jans has made a number of very relevant points for determining the effects of prenatal factors, particularly in emphasizing the interaction and effects of the postnatal environment, maternal factors, and the subsequent social environment. I would like to show you some data on these very points derived, not from a retrospective approach, but from animal experiments in which it has been possible to actually manipulate the prenatal environment, to control for the postnatal effects of maternal factors, and demonstrate differences in development, behavior, and ultimate susceptibility to somatic disease.