Females with precocious puberty who have low levels of serum gonadotropins and high levels of serum estrogen, or those who have demonstrated an inadequate clinical response to therapy with the luteinizing hormone releasing hormone analog (Lupron, Histerelin, Deslorelin), will be treated with testolactone. Testolactone inhibits aromatase, the last enzyme of estrogen biosynthesis. The goal of treatment is to inhibit estrogen secretion and thus delay secondary sexual maturation and epiphyseal closure until the normal age. The intent is to alleviate the psychological problems and short stature frequently associated with this disorder. Throughout therapy, patients will receive frequent clinical, hormonal, and toxicological monitoring. The initial treatment period will be six months. If patients respond to the treatment and tolerate it well, testolactone will be given until puberty is desired. Patients who exhibit pubertal levels of serum gonadotropins during testolactone therapy, indicating the onset of secondary, gonadotropin-dependent puberty, will receive an LHRH analog in addition to testolactone.