Studies of alcohol consumption, although somewhat inconsistent, have shown a relationship between prenatal alcohol exposure, growth retardation, and morphologic abnormalities. The inconsistency of the observed effects may be a result of differential exposure, exposure at different times during pregnancy, methodologic problems with identification and measurement, or inadequate control for risk factors that covary with alcohol consumption. There have been too few studies to assess accurately the effect of drinking on development beyond the neonatal period. Some studies have found that infants of heavy drinking mothers are growth-retarded and developmentally delayed throughout the preschool ages. These effects seem to be related to prenatal alcohol exposure in a dose-response manner. While these studies await replication, these findings do parallel those reported for children with FAS and children of alcoholic mothers. Laboratory research has also shown that toxic exposures during pregnancy affect the fetus differentially as the exposure dose increases, beginning with behavioral or central nervous system effects, then growth and morphologic effects. FAS patients are affected in all of these domains with cognitive and behavioral problems, growth retardation, and morphologic abnormalities. Children who have been prenatally exposed to moderate levels of alcohol in the MHPCD sample also show deficits in each of these domains, illustrating a continuum of response. Thus, the consequences of heavy drinking seem to represent the more severe end of a continuum of effects seen in the offspring of alcoholics.(ABSTRACT TRUNCATED AT 250 WORDS)