This study will evaluate the genital neoplastic and overall health effects of prenatal exposure to diethylstilbestrol (DES). The subjects are females whose mothers participated in a double blind trial of the use of DES in pregnancy in 1951-52. Baseline data have been obtained by health history questionnaire for a total of 344 exposed and 302 unexposed offspring (81 percent of the liveborn daughters). Neoplastic changes of the cervix and vagina (squamous dysplasia and carcinoma in situ) and ovarian and parovarian cysts have been noted slightly more frequently in the exposed. One ovarian carcinoma has occurred in the exposed and one stromal sarcoma of the uterus and a squamous cell carcinoma of the cervix among the unexposed. All subjects will be evaluated by annual health questionnaire. In addition, approximately 185 exposed and 80 unexposed will receive annual examinations at a special DES clinic. Medical records are obtained in the case of all hospitalizations for each subject and pathology slides will be obtained for review of all malignant or premalignant (dysplasia and carcinoma in situ) genital lesions for those participants (approximately 400) who are not being followed at the special DES clinic. The findings between the exposed and unexposed groups will be compared. The follow-up of this unique group of daughters all of whose mothers participated in the same double blind trial allows a conrolled assessment of the health effects of prenatal DES exposure. Studies on this cohort can help to identify and new health risk to DES-exposed daulghters in the future.