Plasma LH and FSH responses to GnRH (100 micrograms, iv) were measured in four female transsexuals with normal ovulatory menstrual cycles before and after the administration of 2.0 mg diethylstilbestrol (DES) daily for 7 days. One normal ovulatory woman was also studied in the early follicular phase of the menstrual cycle. No difference was found in the augmented response of the four female transsexuals to GnRH after DES priming from that of the normal adult female. The augmented response to GnRH found in the female transsexuals after DES treatment provides evidence that hypothalamic-pituitary feedback control is normal in the female transsexuals studied.