To determine whether in vitro fertilization (IVF) as a method of conception is associated with an increased risk for congenital malformations or developmental dysfunction, we performed a general physical examination for malformations, neurologic examination, developmental examination (Bayley Scales), echocardiography, electrocardiography, abdominal ultrasound study, and, when possible, cranial ultrasound examination on a cohort of 83 IVF children and 93 matched non-IVF children. Major malformations were found in two IVF and one non-IVF subject; the rates were not significantly different. The mean Mental Development Index scores for IVF subjects and the comparison group were 115 +/- 13 and 111 +/- 13, respectively (p = 0.12). The mean Psychomotor Development Index scores were 114 +/- 14 and 108 +/- 15 (p = 0.04). Based on these small numbers but extensive evaluation, we found no association between conception by IVF and an increased risk for congenital malformations. Likewise, children conceived by IVF showed no evidence of developmental delay. Their high average achievement on the Bayley tests probably resulted from the exceptional motivation of their parents ("wantedness") and their generally high socioeconomic status.