Maternal alcohol and pentazocine abuse: neonatal behavior and morphology in an opposite-sex twin pair.

A pair of preterm, opposite-sex twins were examined during the lying-in period for behavioral and morphological effects of maternal alcohol and pentazocine abuse during pregnancy. A few morphological features typical of fetal alcohol syndrome were observed in each infant, and the male infant only was above the standardized mean in minor physical anomalies. The male's behavioral scores were more likely to be deviant from the standardized mean than the female's. Specifically, the male was more irritable, both spontaneously and in response to specific stimuli; highly active while awake and handled for the presentation of stimuli; more active than average during sleep; and low on ratings that reflect the attitude of the examiner toward the infant. These findings imply individual and gender differences in behavioral susceptibility to teratogens.