True hermaphroditism: a new case with complex mosaicism.

True hermaphroditism is a very rare disorder of human sexual differentiation. In the medical literature, more than 450 cases are described, and about 250 true hermaphrodites have been subjected to chromosome studies. A 21-year-old "man" was examined because of genital and phenotypic abnormalities: clinical, surgical and laboratory investigations showed a true hermaphroditism, with a quadruple mosaicism 45,X/46,XX/46,XY/47,XXY. We believe that this is the first case in which this peculiar type of multiple mosaicism has been documented.