A survey of attitudes of pediatricians, child neurologists, and pediatric surgeons toward Down syndrome is compared with a similar study reported in 1975. A contemporary physician would be much more aggressive in treating a child with Down syndrome who has associated anomalies such as duodenal atresia or congenital heart disease. Few would recommend institutionalization of a person with Down syndrome; the majority expect that such individuals could productively spend their adult lives in group homes. Positive changes in physicians' attitudes during the past 15 years have been influenced by parent advocacy groups, court decisions, and studies showing that the ultimate intellectual and social skills of Down syndrome children are greater than was previously believed. The most prominent variable associated with attitudes was the physician's age: the older the physician, the more likely he or she would be nonsupportive of active treatment on behalf of the Down syndrome individual. These findings suggest that ongoing education of medical students and pediatric residents in the field of developmental disabilities and bioethics is required in order to promote well-informed advocacy for the mentally handicapped.