[New evidence regarding the etiology and pathogenesis of true hermaphrodites]

New evidence has become available regarding certain aspects of the aetiology and pathogenesis of true hermaphroditism. It is evident that the presence of a Y-chromosome in the karyotype of the true hermaphrodite predisposes to the formation of a testis on the one side and an ovary or an ovotestis on the other side. The presence of 46,XX-chromosome complement, however, more commonly results in an ovotestis on the one side and an ovary on the other side. The formation of an ovotestis is possibly due to a difference in the presence of H-Y-antigen in the cells of the ovarian and the testicular portion. The development of the Müllerian and Wolffian ducts is much more interdependent than has previously been known. No cases have been described where two ducts, both of Wolffian and Müllerian origin, were found next to an ovotestis. In humans, fetal androgen does not change hypothalamic activity to a monophasic pattern or produce male sexual behaviour, according to the evidence found in the true hermaphrodites investigated by us.