1. Department of Clinical Physiopathology; Sexual Medicine and Andrology Unit; Florence; Italy
2. Quality Laboratory Control Center; Azienda Ospedaliera-Universitaria Careggi; Florence; Italy
3. Department of Biomedical Sciences; Applied Biology Section; University of Siena; Siena; Italy
4. Sterility Center; UO Gynecology and Obstetrics; Hospital of Pescia; Pescia; Italy
5. Medical School and Hospital; University of Pisa; Pisa; Italy
6. Fertility Center of the Department of Sciences for Woman and Child's Health; University of Florence; Florence; Italy
7. Laboratory of Seminology-Sperm Bank; Department of Experimental Medicine; University of Rome “La Sapienza”; Rome; Italy
8. Department of Statistics; University of Florence; Florence; Italy