[1] Stanford Univ, Div Reprod Endocrinol & Infertil, Obstet & Gynecol, Stanford, CA 94305 USA
[2] Univ Michigan, Biostat, Ann Arbor, MI 48109 USA
[3] Michigan State Univ, Obstet & Gynecol & Reprod Biol, E Lansing, MI 48824 USA
[4] Univ Florida, Coll Med, Physiol & Funct Genom, Gainesville, FL USA