Random samples of pediatricians, family practitioners and pediatric surgeons were surveyed with a questionnaire, which included three questions regarding their decisions about treatment of duodenal atresia in two hypothetical infants with Down syndrome, one with complete trisomy 21 and one with mosaicism. Results showed that doctors are more likely now to advocate surgery than in the past. Pediatricians and family practitioners had similar views, but pediatricians were more assertive about treatment if parents refused. Pediatric surgeons had the most pessimistic outlook and a greater number would not encourage surgery. There was a relationship between the doctors' prognostications and their decisions about treatment. These results emphasize the importance of ensuring that doctors have accurate perceptions about the capabilities of individuals born with Down syndrome.