Abstract
Almost 20 per cent of 143 children referred to a mental retardation project were found not to be mentally retarded. About 5 per cent had preventable forms of mental retardation resulting from conditions such as hypothyroidism, phenylketonuria and galactosemia.
Continued sympathetic care by the physician is mandatory. Except in forms of mental retardation known to be hereditary, such as Tay-Sachs disease, one may advise parents that the chance is quite small (about 3 per cent) that more mentally retarded children will be born to them.