Pathophysiological events occurring during fetal development are increasingly recognized as influencing atherosclerosis throughout childhood and adolescence. Maternal hypercholesterolemia during pregnancy markedly increases fatty streak formation in human fetal arteries. Although fetal fatty streaks partially regress under normocholesterolemic conditions, progression of atherosclerosis in children of hypercholesterolemic mothers is much faster than in children of normocholesterolemic mothers. This cannot be accounted for by conventional risk factors of atherosclerosis or inherited genetic differences. The nature of the persistent changes in the fetal arterial wall responsible for increased atherogenesis in children and the mechanisms by which maternal hypercholesterolemia induces these changes need to be investigated, because they may offer important insights into the pathogenesis of atherosclerosis and because targeted interventions in mothers during pregnancy may yield considerable long-term benefits.