Genital ambiguity in the newborn baby should be considered to be a medical emergency. Although a considerable number of embryologic, physiologic and hormonal events that effect normal sexual differentiation are well known, our understanding of sexual differentiation is still uncompleted at this point. In the female, XX infant, virilisation may occur in the presence of normals gonads, on the other hand, a female aspect may be present in a XY male infant in the presence of tests. Diagnostic procedures in intersexual states are very complex and may include specific laboratory tests, diagnostic imaging and the biopsy of the gonads. The decisions concerning the management of the child involve emotionally highly-charged value judgments.