Of 50 consecutive women with partial seizures of temporal lobe origin (temporal lobe epilepsy [TLE]) evaluated for reproductive dysfunction, 28 had menstrual problems. Of those, 19 had reproductive endocrine disorders. Polycystic ovarian syndrome and hypogonadotropic hypogonadism occurred significantly more often in women with TLE than in the general female population. Polycystic ovarian syndrome was associated with predominantly left-sided lateralization of interictal epileptic discharges; hypogonadotropic hypogonadism was more commonly found with right-sided discharges. Hyposexuality occurred more often in women with predominantly right-sided interictal epileptic discharges and was associated with low serum luteinizing hormone levels. There are several possible interpretations: epileptic discharges in medial temporal limbic structures may disrupt hypothalamic regulation of pituitary gonadotropin secretion; anovulatory cycles of reproductive endocrine disorders may promote the development of epileptic discharges; and TLE and some associated reproductive endocrine disorders may represent the parallel effects of prenatal factors common to the development of the brain and the reproductive system.