or fetal alcohol syndrome facial features (Table 1). This is important because it suggests that the prenatal conditions of the siblings reared apart may be comparable, even when the postnatal environments are not, which allows for greater confidence that any sibling behavioral differences are likely specific to postnatal, rather than prenatal, environmental influences. The striking differences in rearing environments of the siblings allows for analyses that control for the effects of shared genes while identifying environmental features that may lead a sibling in one home to develop problems but lead a sibling in the other home to remain symptom free.
