Assisted reproductive technologies (ART) predispose the offspring to vascular dysfunction, arterial hypertension, and hypoxic pulmonary hypertension. Recently, cardiac remodeling and dysfunction during fetal and early postnatal life have been reported in offspring of ART, but it is not known whether these cardiac alterations persist later in life and whether confounding factors contribute to this problem. We, therefore, assessed cardiac function and pulmonary artery pressure by echocardiography in 54 healthy children conceived by ART (mean age 11.5 ± 2.4 yr) and 54 age-matched (12.2 ± 2.3 yr) and sex-matched control children. Because ART is often associated with low birth weight and prematurity, two potential confounders associated with cardiac dysfunction, only singletons born with normal birth weight at term were studied. Moreover, because cardiac remodeling in infants conceived by ART was observed in utero, a situation associated with increased right heart load, we also assessed cardiac function during high-altitude exposure, a condition associated with hypoxic pulmonary hypertension-induced right ventricular overload. We found that, while at low altitude cardiac morphometry and function was not different between children conceived by ART and control children, under the stressful conditions of high-altitude-induced pressure overload and hypoxia, larger right ventricular end-diastolic area and diastolic dysfunction (evidenced by lower E-wave tissue Doppler velocity and A-wave tissue Doppler velocity of the lateral tricuspid annulus) were detectable in children and adolescents conceived by ART. In conclusion, right ventricular dysfunction persists in children and adolescents conceived by ART. These cardiac alterations appear to be related to ART per se rather than to low birth weight or prematurity.