[1] Stanford Univ, Sch Med, Dept Obstet & Gynecol, Div Reprod Biol, Stanford, CA 94305 USA
[2] Stanford Univ, Sch Med, Dept Comparat Med, Stanford, CA 94305 USA
[3] NV Organon, Dept Pharmacol, NL-5340 BH Oss, Netherlands
[4] NV Organon, Lead Discovery Unit, NL-5340 BH Oss, Netherlands