1. Centre of Reproductive Medicine and Andrology (J.W., C.M.L., J.-B.S., A.P., S.W., M.D., O.S.D., M.S., J.G.), University Clinics, 48149 Muenster, Germany;
2. Institute of Biomedicine (T.H.), Department of Physiology, University of Turku, 20520 Turku, Finland