1. Division of Infertility and Reproductive Endocrinology, Department of Obstetrics and Gynecology (S.B., A.S., C.C., K.B.), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
2. Center for Clinical Epidemiology and Biostatistics (S.B., S.R., K.B.), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
3. The Wistar Institute (H.R.), University of Pennsylvania, Philadelphia, Pennsylvania 19104