[1] Yijishan Hosp, Wannan Med Coll, Inst Reprod Med, Wuhu 241001, Peoples R China
[2] Natl Res Inst Family Planning, Beijing 100081, Peoples R China
[3] Peking Union Med Coll, Beijing 100081, Peoples R China
[4] Peking Univ First Hosp, Androl Ctr, Beijing 100034, Peoples R China
[5] World Hlth Org Collaborating Ctr Res Human Reprod, Beijing 100081, Peoples R China