1. Edinburgh Assisted Conception Programme, EFREC, Royal Infirmary of Edinburgh, 51 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SA, UK
2. Ospedale Versilia, Centro di Procreazione medicalmente assistita, Lido di Camaiore, Italy
3. ANDROFERT, Andrology and Human Reproduction Clinic, Campinas, Brazil; Division of Urology, Department of Surgery, University of Campinas (UNICAMP), Campinas, Brazil
4. Faculty of Health, Aarhus University, Aarhus, Denmark