['Reduced fertilization rates in women with minor endometriosis may be the result of direct effects on the ovary or to primary dysfunction within the hypothalamic-pituitary-ovarian axis. This controlled study was designed to examine the steroidogenic potential of luteinized granulosa cells in women with minor endometriosis.', 'Granulosa cells were harvested at oocyte recovery and incubated for 3 hr in increasing concentrations of luteinizing hormone (LH). The dissociation constant for added concentrations of LH was computed (as Km LH) and the results were compared between women with endometriosis and controls.', 'Women with minor endometriosis had a higher dissociation constant than women with tubal damage [Km 0.98 (0.58-9.24) versus 0.33 (0.28-0.72) ng/mL, P = 0.019], indicating reduced sensitivity to LH.'] Are pre-ovulatory granulosa cells of infertile women with endometriosis less sensitive to luteinizing hormone?