1. Department of Pediatrics, John Radcliffe Hospital (M.L.A., K.K.L.O., N.D., D.B.D.), Oxford, United Kingdom OX3 9DU
2. Reproductive Medicine Laboratory, University of Edinburgh Center for Reproductive Biology (D.J.M.), Edinburgh EH11 9EW, Scotland
3. the Biochemistry, Endocrinology, and Metabolism Unit, Institute of Child Health (L.C., M.A.P.), London, United Kingdom WC1N 1AH
4. the Department of Clinical Biochemistry, St. Bartholomew’s Hospital (L.P.), London, United Kingdom EC1A 7BE