Genetic males who have cloacal exstrophy, a rare, severe pelvic field defect that leads to aphallia, traditionally have been socially, legally, and surgically sex-assigned female at birth and reared female, despite a male karyotype and a typical male prenatal hormonal milieu. Psychosexual development in such children previously has been unknown. Studies of 29 children revealed that despite the absence of the typical postnatal and pubertal androgen surges and the presence of female genitalia, all female-assigned subjects displayed a marked male-typical shift in psychosocial and psychosexual development. Nearly half of them have declared themselves male. Psychosexual development, including gender identity, in genetic and hormonal male neonates seems to be influenced heavily by prenatal androgen exposure. The clinical practice of surgical sex assignment at birth requires re-evaluation.