<h3>Introduction</h3> There are five physical variables of sex (Money et al, 1955), namely, the chromosomal, gonadal, hormonal, internal morphologic, and external morphologic. In addition, there are two psychosocial variables, the sex of assignment and rearing and the gender role and psychosexual identity subsequently differentiated. The optimal condition of sexual differentiation, physical and psychic, is congruity of all seven variables. Such an optimum, however, is not always achieved, in which case a clinically recognizable syndrome of sexual abnormality, physical, and/or psychic, exists. One such clinical condition is Klinefelter's syndrome. The incongruity here is chromosomal. The condition may, in fact, be thought of as representing cytogenetic hermaphroditism, since the sex chromosome complement is ambiguous. The chromosome count is 47, XXY, instead of 46, XY as is typical for a male, or 46, XX as is typical for the female. Patients with Klinefelter's syndrome are phenotypic males,