Patients with ambiguous genitalia have disorders of sexual development (DSD), previously termed intersex conditions. These conditions arise from chromosomal, gonadal, or anatomic abnormalities in the pathway of sexual differentiation. Physical findings in patients with DSD may range from an apparently normal phenotype to complete ambiguity. DSD is considered an endocrine emergency because in the majority of cases the genital findings may be accompanied by life-threatening electrolyte abnormalities, hypotension, and shock. Ninety percent of infants with ambiguous genitalia have congenital adrenal hyperplasia (CAH), and more than one half of these patients experience significant sodium loss. However, no individual patient should be assumed to have virilizing congenital adrenal hyperplasia. In addition to the potential medical emergency, the psychological stress to the family cannot be overstated.