This chapter reviews what one knows about the neurological and cognitive effects of antiepileptic drugs (AEDs) on the developing fetus. The combined effects and interactions of genes and the environment determine neurodevelopment. Thus, a child's neurodevelopment is affected by that child's inheritance, the mother's age at the time of pregnancy, the child's birth order, the mother's health during the pregnancy, drug exposure, obstetric complications, the nutritional status of the mother and child, childhood illnesses, social and economic status of the family, the mother's and father's educational levels, as well as the child's educational opportunities. A variety of factors may contribute to the neurodevelopmental deficits observed in the children of women with epilepsy. Children born to mothers with epilepsy have a slightly higher risk of neurodevelopmental difficulties, which can be reduced by good health practices, good seizure control, and using only as much antiepileptic medication as is necessary for seizure control.