PHALLIC GROWTH AFTER HCG - A CLINICAL INDEX OF ANDROGEN RESPONSIVENESS

Clinical and hormonal responses to a standard three-day human chorioni c gonadotropin (hCG)-stimulation test (1,500 IU given intramuscularly for three days) were studied in six neonates with ambiguous genitalia. All patients were eventually determined to be 46,XY genetic males wit h a microphallus and various other genital abnormalities. None had an enzymatic defect in steroidogenesis or a 5alpha-reductase deficiency, as determined by standard adrenocorticotropic hormone (ACTH) and hCG t esting. All patients demonstrated penile growth (0.25 to 0.75 cm) with in five days of hCG administration, with four of six patients achievin g a normal penile length (>2.0 cm) by 48 hours after the last of three daily hCG injections. Androgen responsiveness suggested by phallic gr owth may help support a male sex assignment in such infants.