1. Department of Obstetrics and Gynecology (C.R.N., S.L.C., R.A.R.P.), Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Palo Alto, California 94304
2. Department of Obstetrics and Gynecology (V.L.B.), Division of Reproductive Endocrinology and Infertility, Stanford University Medical Center, Palo Alto, California 94305