1. Andrology Unit, Department of Dermatology and Allergy; University Hospital Bonn; Bonn Germany
2. Department of Urology; University Hospital Cologne; Cologne Germany
3. Department of Urology, Pediatric Urology and Andrology; Justus Liebig University; Giessen Germany
4. Hessian Centre of Reproductive Medicine; Justus Liebig University; Giessen Germany