1. Institute for Stem Cell Biology and Regenerative Medicine, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Palo Alto, California, USA
2. Center of Reproductive Medicine and Andrology, University of Muenster, Muenster, Germany
3. Center for Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA
4. Department of Urology, University of California, San Francisco, San Francisco, California, USA
5. Sheba Medical Center, Tel Hashomer, Israel