1. Department of Genetics and Cell Biology, Basic Medical College, Qingdao University, Qingdao, Shandong, China
2. Department of Reproductive Medicine, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
3. Institute for Stem Cell Biology and Regenerative Medicine, School of Medicine, Stanford University, Stanford, CA, USA
4. The Affiliated Hospital of Qingdao University and Biomedical Sciences Institute of Qingdao University (Qingdao Branch of SJTU Bio-X Institutes), Qingdao University, Qingdao, China
5. Department of Obstetrics, Gynaecology, and Reproductive Sciences, School of Medicine, Yale University, New Haven, CT, USA
6. Greenwich Hospital Fertility Center, Greenwich Hospital, Greenwich, CT, USA