Assess the Effect of Daily Treatment of Vardenafil 20mg or Sildenafil 100mg and Placebo on Sperm Function

A Randomized, Double-blind, Placebo Controlled, Parallel Arm, Multicenter Trial Assessing the Effect of Daily Treatment of Vardenafil 20 mg or Sildenafil 100 mg Compared to Placebo on Spermatogenesis

Assess the effect of daily treatment of vardenafil 20mg or sildenafil 100mg and placebo on sperm function

Inclusion Criteria:

• Healthy male subjects or men with ED aged 25 - 64
• Baseline sperm conc. of > 20 mio / ml- Normal World Health Organization A+B+C sperm mortality > 50%- Normal sperm morphology (WHO, 1992 manual criteria) > 30% and - 1.0 mL ejaculate volume at each of the 3 analyses during the screening phase.

Exclusion Criteria:

• Presence of any psychological or physiological abnormalities that in the opinion of the Investigator would significantly impair sexual performance or ability to provide semen samples according to the protocol- Spinal cord injury
• History of surgical prostatectomy
• Other exclusion criteria apply according to US Product Information