The objective of this contract is to provide continued follow-up of surviving members of the well-characterized DES-exposed cohorts which will be used to estimate cancer risks in the entire population of approximately 10 million exposed individuals. In addition, existing cohorts will be combined and extended to include previously unstudied exposed individuals in the families, so the total resource will add value to the existing smaller components. Finally, the feasibility of identifying a cohort of grandchildren will be investigated. This work is being supported by the Environmental Epidemiology Branch (EEB), Epidemiology & Biostatistics Program (EBP), Division of Cancer Etiology (DCE) of the National Cancer Institute (NCI).