Recent research in medical genetics and congenital disorders has implications for special education in that it calls into question long-standing suppositions about mildly handicapped populations. Rather than being of unknown or cultural origin, many learning disabilities or cases of mild retardation are due to medically diagnosable, congenital syndromes. The cognitive patterns of Fetal Alcohol Syndrome, sex chromosome abnormalities, multiple anomaly syndromes, phenylketonuria, Tourette syndrome, and several other inherited syndromes are discussed, and suggestions are given for differential special education management.