1. Department of Reproduction, Affiliated Dongguan Hospital, Southern Medical University, Dongguan, Guangdong 523059, P.R. China
2. Department of Urology, Taizhou Central Hospital (Taizhou University Hospital), Zhejiang, Taizhou 318000, P.R. China
3. Department of Urology, The First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, P.R. China
4. Reproductive Center of Medicine, The First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, P.R. China