Current Status of Teratology

Abstract

Experimental teratology in the modern sense can be said to have begun in the 1940s when Warkany and his associates (Warkany and Nelson, 1940; Warkany and Schraffenberger, 1947; and others) first forcefully called attention to the fact tht environmental factors such as maternal dietary deficiencies and X-irradiation could adversely affect intrauterine development in mammals. Earlier studies in which amphibian, fish, and chick embryos had been subjected to altered environments had shown these forms also to be quite susceptible to unfavorable influences during development, but experiments of this type were not generally accepted as purporting similar vulnerability for higher animals. It was widely assumed in biology and in medicine that the mammalian embryo developed within the virtually impervious shelter of the uterus and the maternal body where it was protected from extrinsic factors. This view was consistent with the generally held opinion that most aspects of normal as well as abnormal development were genetically determined, after the rediscovery of the Mendelian principles of inheritance at the beginning of the twentieth century. Although there were published accounts that terata had been observed after exposure of pregnant women and animals to ionizing radiations (Goldstein and Murphy, 1929), the fundamental implication that mammalian embryos were susceptible to environmental factors was not immediately grasped.