['To compare the prevalence of endometriosis and its different stages in infertile women and women not exposed to spermatozoa.', 'Prospective study.', 'Artificial insemination donor program at a university hospital.', 'One hundred fifty women unable to conceive because they had not been exposed to spermatozoa (134 with azoospermic partner, 10 with an HIV-positive partner, and 6 without a male partner). Controls were 750 women in infertile couples in which the male partner had normal sperm.', 'Laparoscopy was systematically performed in a blinded manner in both groups as part of the infertility work-up.', 'Diagnosis of endometriosis.', 'In unexposed women and controls, the prevalence of endometriosis was similar (32% and 34.5%). Rates of stage I disease were also similar in both groups (26% and 19.3%). There was a significant trend toward higher stages of endometriosis in infertile women (stage II disease, 3.3% vs. 5.7%; stage III disease, 1.3% vs. 3.1%; stage IV disease, 1.3% vs. 6.4%). Endometriosis was not associated with the few demographic characteristics that differed between groups.'] Are women who exposed to spermatozoa and infertile women have similar rates of stage I endometriosis?