BEHAVIORAL TERATOGENESIS - AN EXTENSION TO THE TERATOGENESIS OF FUNCTIONS

Major malformations correspond to pathology during the first 2 months of gestation. Thereafter, histological and biochemical abnormalities c an result from different negative maternal incidents and, without obvi ous malformations, change the phenotype of the conceptus. These abnorm alities lead to essentially functional disorders often compatible with life and to more or less serious handicaps. All systems, when they ar rive at such a stage of development, can be theoretically involved. Th e central nervous system (CNS) offers a very clear example of such wea knesses because its maturation is particularly long and susceptible to changes even after birth. The steps of this maturation overlap and fo rm a continuum reflected in the pathology. Mental retardation occurrin g in children born of mothers who were subjected to atomic radiation, or ingested methylmercury from industrial waste, or who suffered the e ffects of lead, alcohol or tobacco constitutes a clear clinical exampl e. Animal experiments confirm these data, adding pathogenic explanatio ns. These experiments also explore the possible consequences that some medical techniques such as modern reproductive technology, for exampl e embryo freezing, can have on the development of the conceptus. Toxic substances or drugs can also be responsible for such abnormalities th rough a genetic attack on spermatogenesis. Behavioral teratogenesis al so opens a larger persepective related to the optimal quality of the c onceptus and the determining factors, from stress or dietary factors d uring apparently normal pregnancy to paternal age at the moment of con ception. Finally, given that other systems than the CNS can be involve d in histological or biochemical abnormalities, such as the reproducti ve system, we must ask what other types of functional pathology can be induced by interventions on gametes, the embryo and the fetus. Thus, behavioral teratogenesis leads to the teratogenesis of functions.