1. Vincent Center for Reproductive Biology (J.H.P., J.M.T.), Department of Obstetrics and Gynecology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
2. Harvard Stem Cell Institute (L.D., J.M.T.), Harvard University, Cambridge, Massachusetts 02138
3. Department of Pathology (S.K.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215
4. Department of Obstetrics and Gynecology (B.S.L.), Severance Hospital, Yonsei University College of Medicine, Seoul, Korea 120-752