1. Laboratory of Neuroendocrinology, Department of Neurobiology, The Babraham Institute (R.A.B., W.P.U., J.E.R.), Cambridge CB2 4AT, United Kingdom;
2. Departments of Pediatrics (V.P.), Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan 48109
3. Reproductive Sciences Program (V.P., D.L.F.), University of Michigan, Ann Arbor, Michigan 48109
4. Ecology and Evolutionary Biology (D.L.F.), University of Michigan, Ann Arbor, Michigan 48109