Alcohol exposure in utero affects growth and morphology, and produces FAS, adverse cognitive outcomes, and poorer linguistic abilities and deficits in attention and memory. Maternal smoking, which is widespread in pregnancy, has been associated with physical, cognitive, and behavioral effects in offspring. The effects of fetal exposure to cocaine are more controversial, but increasing evidence identifies a pattern of decreased neonatal head circumference, decreased adaptability to stress, including a disruption in the habituation response in infants, and impaired attention. The literature on the effects of in utero exposure to marijuana is thus far inconclusive, but there is compelling evidence for its producing decreased birth weight and length and deleterious cognitive and attentional effects in some preschool and early school-age samples. Of the widely prescribed medications used in psychiatric practice, evidence for the deleterious effects of lithium and the anticonvulsants carbamazepine and depakote is well-established and compelling. More prospective studies are required before the safety of the atypical antipsychotics and the newer antidepressants is established. Difficulties of standardizing amount, timing, and patterns of use, as well as the confounding effect of the risk factors, must be carefully considered when interpreting the results of outcome studies, especially those regarding substances of abuse.