1. Reproductive Sciences Program and Department of Biology (K.S.M., D.L.F.), University of Michigan, Ann Arbor, Michigan 48109-0404
2. the Departments of Obstetrics and Gynecology and Molecular, Cellular, and Developmental Biology, Yale University (R.I.W.), New Haven, Connecticut 06520-8063
3. Department of Obstetrics and Gynecology and Biology (D.L.F.), University of Michigan, Ann Arbor, Michigan 48109-0404