1. Division of Reproductive Biology (S.P., M.H., M.F., M.C.), Department of Obstetrics and Gynecology, Stanford, University School of Medicine, Stanford, California 94305
2. Department of Medical Sciences (S.P., L.P.), University of Milan, Lab of Experimental Endocrinology, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, Milano 20095, Italy