Thirty years ago, pediatric residents were taught that trisomy 13 and 18 were lethal congenital anomalies. Parents were told that these conditions were incompatible with life. There was a tacit consensus that life-sustaining treatment was not medically indicated.1 Clinical experience usually was consistent with this self-fulfilling prophecy.
Occasionally, though, some infants with these conditions did survive. The children were invariably institutionalized and described as severely impaired.2 These case reports were considered as the rare exceptions that proved the rule.