Most males with precocious puberty who have been referred to NIH have been successfully treated under protocol 79-CH-0112 "Treatment of True Precocious Puberty with a Long-Acting Luteinizing Hormone Releasing Hormone Analog (D-Trp6-Pro9-Net-LHRH)." A subset of these patients, however, all of whom had familial male isosexual precocity, had an inadequate response to LHRH analog as demonstrated by high serum testosterone levels, rapid advancement in bone age, testicular growth, sperm production, and lack of regression of secondary sex characteristics. These patients had low baseline gonadotropin levels and lacked a pubertal response to LHRH, whereas the patients who had responded to LHRH analog all had clear evidence of central precocious puberty.