1. Korea Institute for Public Sperm Bank, Busan 49241, Korea
2. Department of Obstetrics and Gynecology, College of Medicine, Ulsan University Hospital, Ulsan 44033, Korea
3. Department of Obstetrics and Gynecology, Pusan National University School of Medicine, Pusan National University Hospital, Busan 49241, Korea
4. Department of Cardiothoracic Surgery, Dong-A University Hospital, Busan 602-812, Korea
5. Department of Obstetrics and Gynecology, Sungkyunkwan University School of Medicine, 51353 Changwon, Korea