Developmental endocrine influences on gender identity: implications for management of disorders of sex development

When a baby is born, the first medical pronouncement is usually, "It's a boy," or "It's a girl." In most cases, this pronouncement is based simply upon the appearance of the child's external genitalia. Due to variations in the process of sexual differentiation, sometimes the gender that should be assigned is not apparent from inspection of the external genitalia, either because they are "ambiguous" or because their appearance is not congruent with the internal anatomy. Decisions must be made not only about the most appropriate gender to assign the infant but also about the medical and rearing practices that will facilitate optimal psychological development and quality of life for the affected individual. This article will review the approach to managing gender disorders that has evolved since the 1950s. Three issues are identified as central to current shifts that are occurring in the management of these disorders: (a) increased understanding of the biological substrates of gender identity; (b) questions regarding the indications for irreversible cosmetic genital surgeries as a means of reinforcing gender assignments in infancy, and (c) ethical issues pertaining to informed consent and who is entitled to give it, particularly with regard to surgical gender reassignments in infancy. In keeping with the neuropsychiatry theme of this issue, the focus of this article is on prenatal sexual differentiation of the brain as it pertains to the question of psychosexual neutrality at birth.