Alteration of granulosa cell apoptosis in various groups. Apoptosis was measured by staining the cell membrane with annexin V- fluorescein-5-isothiocyanate FITC, staining the nucleus with propidium iodide (PI), and measuring the proportion of Annexin V-positive or PI-positive cells by flow cytometry. The top panel shows a scatter plot of each group [male factor (M), endometriosis (E), other female factors (O), and polycystic ovary syndrome (P)] in a flow cytometer. The bottom panel shows quantitative flow cytometry data. The p-value for each group versus the male factor group was determined by an unpaired t-test.