The cardiometabolic health of children conceived by assisted reproductive technologies (ART) compared with children conceived without medical assistance is unclear. Although the majority of published studies evaluating height, weight, and body mass index have not found differences by method of conception, some studies have indicated differences in adiposity by more direct measures such as skinfolds and dual X-ray absorptiometry. Far fewer studies have investigated other cardiometabolic characteristics, such as blood pressure and measures of lipid and glucose metabolism. Of these studies, some indications of increased blood pressure and recent findings of vascular dysfunction among children conceived by ART compared with children conceived without ART warrant further investigation. Epigenetic differences may be the global mechanism at work, resulting from different aspects of ART treatment, such as ovarian stimulation, in vitro culture, and manipulation of sperm, among other considerations. Fetal growth and placental development may serve as mediators of these effects. Future studies should consider recruiting sufficient numbers of ART and non-ART conceived multiples and collect information on indicators of cardiometabolic health in the parents. Despite some advantages of sibling cohorts in developmental origins research, its feasibility and utility for investigating health of children conceived by ART remains debatable.