Applications of Epidemiological Methods to the Study of Congenital Malformations in Man

INTRODUCTION. PLANNED observation of phenomena as they occur must be the main tool of investigation in man, experiments as in animals being impossible, but planned observation and analysis is surely the very essence of epidemiology. Yet it would seem to be characteristic of work on human anomalies that many people are working directly on these, or on relevant problems, in narrow fields and making disconnected contributions to knowledge. My general thesis is that many good opportunities for epidemiological work are being wasted because the hypotheses arising from different sources are not being tested adequately by the epidemiological method.