Ambiguous Genitalia in the Newborn

Presence of ambiguous genitalia in newborns typically represents a medical and psychosocial emergency. The term "ambiguous genitalia" refers to genitalia that is not clearly male or female in the spectrum of sexual development. Patients may present as predominantly male but may have hypospadias, a small phallus, a scrotum with fewer than two palpable gonads, or a scrotum with separated scrotal sacs. Patients may also present as predominantly female but may have an enlarged clitoris, occasionally appearing to be a phallus; fused labioscrotal folds; an inguinal hernia containing a gonad; or a shortened vulva with a single opening. Population studies suggest that the frequency of children born with any degree of ambiguous genitalia, including hypospadias, ranges from 1 in 4500 to 1 in 30,000 patients. The process of sexual differentiation in such infants is complex and is aided by recent advances in molecular biology and genetic analysis. These disorders may be categorized according to the stage of development at which the disruption of normal development occurred. Sex of rearing may be more difficult to establish for male pseudohermaphrodites because there is evidence that testosterone imprinting on the fetal brain may play a strong role in determination of male sexual orientation despite the outward genital appearance. Traditionally, reconstructive surgery is scheduled in early life to ensure a stable gender identity. Reconstruction of the genitalia also facilitates social acceptance of the child's gender assignment.