1. Family Planning Research Institute; Tongji Medical College; Huazhong University of Science and Technology; Wuhan China
2. Reproductive Medicine Center; Tongji Medical College; Huazhong University of Science and Technology; Wuhan China
3. Hubei Province Human Sperm Bank; Wuhan China
4. Department of Epidemiology and Biostatistics; School of Public Health; Tongji Medical College; Huazhong University of Science and Technology; Wuhan China