Association of Maternal and Fetal Factors With Development of Mental Deficiency

It has been repeated frequently within recent years that mental deficiency is not in itself a clinical entity but rather a symptom present in a large number of diseases of varying etiology.1This symptom, present according to different estimates in from 1 to 2% of the population of the United States, is probably the most serious single public health problem from the point of view of chronicity, cost of care, loss of productive and earning capacity, and tragedy in the family. Within this century the thinking concerning the etiology of this entity has swung from considering the majority of cases of mental deficiency to be of hereditary or familial origin to the belief that only a small minority of cases falls within this category.2As an increasing number of exogenous factors has become causally implicated, the so-called endogenous role of heredity that had previously been applied largely on