The primary focus of our research program is on the effects of prenatal exposure to neurotoxic agents on infant, child, and adolescent neurocognitive and behavioral development. Our 19-year longitudinal study of inner-city, Detroit children prenatally exposed to alcohol at moderate-to-heavy levels has focused on genetic and environmental factors that modify effects of prenatal alcohol exposure on development, how these effects differ from exposure to cocaine and other drugs, and the lowest exposure levels at which effects can be detected. Since 1998, we have also been conducting collaborative research in Cape Town, South Africa, where the incidence of heavy drinking and fetal alcohol syndrome is among the highest in the world. That research is currently focusing on identification of biobehavioral markers of fetal alcohol exposure, such as eyeblink conditioning, and a range of innovative neuroimaging methods with children and infants to advance understanding of the etiology of the fetal alcohol spectrum disorders. In addition, we study effects of environmental contaminant exposure. Our 11-year prospective, longitudinal study on polychlorinated biphenyls (PCBs), a ubiquitous environmental contaminant, was the first to link prenatal PCB exposure to reduced IQ and poorer academic achievement in childhood. We are currently completing a 10-year study on effects of prenatal exposure to methylmercury and other contaminants in a cohort of Inuit children in Arctic Quebec.