Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah; Department of Cell Biology and Physiology, Brigham Young University, Provo, Utah; Andrology and IVF Laboratories, University of Utah School of Medicine, Salt Lake City, Utah. Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah; Andrology and IVF Laboratories, University of Utah School of Medicine, Salt Lake City, Utah. Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah; Andrology and IVF Laboratories, University of Utah School of Medicine, Salt Lake City, Utah; Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah. Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland. Biostatistics and Bioinformatics Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland. IVF and Andrology Laboratories, Center for Advanced Reproductive Care, Iowa City, Iowa. The Emmes Company, LLC, Rockville, Maryland. Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Utah School of Medicine, Salt Lake City, Utah. Andrology and IVF Laboratories, University of Utah School of Medicine, Salt Lake City, Utah. Division of Urology, Department of Surgery, University of Utah School of Medicine, Salt Lake City, Utah. Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania. Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland. Electronic address: mumfords@mail.nih.gov.