This paper reports on follow-up studies of a hermaphroditic male raised from birth as a female because of normal female-appearing genitals. Despite unequivocal assignment to the female sex and the parents' wish that the child be feminine, 'she' had been unswervingly masculine from infancy on. When diagnosed as a genetic and physiologic male at the age of 14 in 1961, 'she' immediately switched to a male role and has from then to now lived without neurosis and with professional and heterosexual success. Recent advances in hormonal chemistry have revealed the patient to have been under the influence, from foetal life on, of a rare sexual hormone enzyme defect that caused the anatomic hermaphroditism but nonetheless allowed for prenatal androgen priming of the brain.