1. Department of Reproductive Medicine, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China
2. Department of Urology, Guangdong General Hospital, Guangdong Academy of Medical Science, Guangzhou, Guangdong, People's Republic of China
3. Department of Urology, Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, People's Republic of China