Effects of Paternal Exposure to Alcohol on Offspring Development

The adverse consequences of maternal alcohol intake during pregnancy on fetal outcome are well-documented (for a review, see Meyer and Riley 1986). However, the possibility that paternal alcohol consumption also may induce deficits in the progeny has received relatively little attention. This is somewhat surprising, as alcoholism appears to be linked genetically with the father in humans (Merikangas 1990; Pickens et al. 1991), and studies indicate that male offspring of alcoholic fathers have behavioral problems and impaired intellectual skills as well as hormonal and nervous system anomalies (see below). This article discusses the possible direct effects of paternal alcohol consumption on fetal development, distinguishing these effects from studies of the genetic heritability of alcoholism. The article also discusses the possibility that such paternal effects may contribute to cognitive and biochemical disturbances that may be associated with altered responses to alcohol that might lead to addiction. For purposes of this review, alcoholism is broadly defined as the excessive and repetitive consumption of alcohol that results in significant disturbances in a person's life, such as preoccupation with drinking to the exclusion of other activities, inability to perform adequately at work, and deterioration of family or other social interactions. In general, the study populations discussed below meet not only these criteria but also others required for a clinical diagnosis of alcoholism. DEFICITS IN THE OFFSPRING OF MALE ALCOHOLICS Many studies have indicated that children of alcoholic fathers often demonstrate impaired cognitive(1) skills and are more likely to be hyperactive than are children of nonalcoholic biological parents (Hegedus et al. 1984; Tartar et al. 1989). These studies generally adopted controls to ensure that the effects were not due to such factors as maternal drug use, socioeconomic variables, race, and psychiatric or medical disorders in the parents. These effects also were observed in children borne of alcoholic biological fathers but raised by nonalcoholic adoptive parents. Sons of alcoholics also have abnormal electrical activity in the brain as measured by the electroencephalograph (EEG) (Begleiter and Projesz 1988; Ehlers et al. 1989; Schuckit et al. 1987a). Moreover, it has been shown that the sons of alcoholics, when compared with sons of nonalcoholic parents, demonstrate abnormal hormonal responses to short-term administration of alcohol (Schuckit 1988; Schuckit et al. 19874b, 1988). Hence, these data seem to suggest that genetic factors of the biological fathers that relate to their drinking behavior may have a significant effect on the intellectual and behavioral development of their offspring. GENETIC BASIS FOR TRANSMISSION OF ALCOHOLISM The foregoing studies generally represent attempts to identify markers for the predisposition for alcoholism. A marker can most easily be understood as a specific trait that may predict whether a person is at risk for developing a medical disorder. For example, blood tests can be used to predict the occurrence of various genetic disorders, including cystic fibrosis and Down syndrome. Researchers are attempting to identify markers that could serve as early indicators of potential susceptibility to alcoholism. Genetic linkage studies are a more useful approach for identifying a genetic basis for alcoholism. These sophisticated molecular biological techniques attempt to establish causal links between disorders and specific genes. Using these techniques, researchers have identified genes responsible for at least some types of Alzheimer's disease, cystic fibrosis, and other genetically transmissible disorders. The discovery of an association between a medical disorder and a specific gene provides a better understanding of the mechanisms underlying the disorder and may therefore provide a basis for improved treatment. …