Information on reproductive history, gynecologic operations, and examinations was analyzed for 338 diethylstilbestrol (DES)-exposed and 298 unexposed women whose mothers participated in an evaluation of DES use in pregnancy 28 years ago. A history of infrequent menses (less often than every 36 days) was reported more commonly by the exposed women (32%) than by the unexposed women (15%) and the mean duration of menstrual flow was also less. A greater number of exposed women than unexposed women experienced primary infertility (53 versus 19). The reasons for these differences are not currently known. Comparison of the outcomes of first pregnancies showed a higher proportion of premature births, spontaneous abortions, and ectopic pregnancies in the exposed women (P less than 0.001). The difference in the occurrence of ectopic pregnancies was statistically significant (8 versus 0; P less than 0.005). An adverse pregnancy outcome was more likely in DES-exposed women with cervicovaginal ridges. However, when the outcome of all pregnancies were considered, 81% of the exposed women had at least one living child. More exposed women than unexposed women had gynecologic surgical procedures, which may, in part, be due to the increased medical surveillance of the exposed group. The spectrum of diseases at operation in both groups was similar. Adnexal masses and pelvic inflammatory disease were more commonly reported among the exposed women while the occurrence of endometriosis in both groups was similar. For the exposed women who had been examined at the Chicago Lying-In Hospital over a 4-year period, epithelial changes in the vagina had disappeared in 32% and cervicovaginal ridges had disappeared in 57%.