In industrialized countries, overweight and obesity are the most common nutritional disorders, showing an increasing prevalence. Overweight children have a high risk for being overweight in adulthood, and therefore are at risk for the disease states associated with obesity, including Type 2 diabetes. Recently, Montgomery and Ekbom (2002), von Kries et al. (2002), and Toschke et al. (2002) have reported a higher prevalence of obesity in children at school entry or as adults whose mothers had smoked during pregnancy. These observations of an increased risk for overweight and obesity have major implications for the understanding of fetal programming by developmental factors and for the prevention of obesity. The strength of the effect of maternal smoking in the final logistic regression model was comparable to that of the other significant risk factors amenable to prevention such as frequent TV viewing/video games and frequent consumption of snacks while watching TV. The offspring of pregnant rats exposed to an active component of tobacco smoke, nicotine, demonstrate both appetitive learning and attentional deficits. As summarized by Levin, Slotkin, and co-workers (1998), these behavioral effects are associated with alterations of the cholinergic, catecholaminergic, and serotonergic neurotransmitter systems of the brain. Alterations of the cholinergic system have been linked to learning deficits, whereas the catecholaminergic and serotonergic systems have been associated with the brain's reward system and feeding behavior, respectively. Therefore, it is postulated that exposure to nicotine in utero due to maternal smoking during pregnancy may result in persistent behavioral effects, including deficits in impulse control. Clinical observations appear to support this concept further: daughters of mothers who smoked during pregnancy were four times more likely to smoke when compared either with the offspring of nonsmokers or to children of women who did not smoke during pregnancy but did smoke after delivery. Together, these data support the hypothesis that obesity in children of mothers who smoked during pregnancy could be due to long-lasting behavioral teratogenic effects of nicotine exposure in utero. The search for additional risk factors for childhood obesity should be expanded because of the detrimental effects of obesity on health quality and the impact on our already-stressed health care capabilities.