Introduction Abnormalities of psychologic functioning in patients with Turner's syndrome are of interest owing to their possible relationship to the well-documented cytogenetic origin of the condition. Turner's syndrome, also known as gonadal aplasia, ovarian agenesis, and gonadal dysgenesis, was first described by Turner in 1938 and has since then been extensively studied and characterized, for example by Haddad and Wilkins, 1959, and Wilkins, 1957. The genetic defect in 80% of the cases is one in which the sex chromatin is negative and the chromosome count 45, XO, instead of the normal 46,XX. Other cases have been shown to be chromatin positive and to have XO/XX, XO/XXX, or other mosaicisms, or to have chromosome deletions or translocations. Shaffer in 1962 first called attention to a peculiar psychologic abnormality in Turner's syndrome that was associated with a Wechsler Performance IQ significantly lower than Verbal IQ. Applying Cohen's