1. Departments of Reproduction and Development (L.J.B., P.E.D.R., E.C.M.K., E.E.H., J.A.G.), 3000 CA Rotterdam, The Netherlands;
2. Gynecology and Obstetrics (E.S.-K., S.C.J.P.G., C.W.B.), Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands;
3. Department of Pharmacology, Research and Development Laboratories, N.V. Organon (M.E.D.G., H.J.K.), 5340 BH Oss, The Netherlands