Yes and no. Several studies have revealed contradictory results in the past.  However, eventually, it was found out that the saddle type and riding position are what leads to infertility or erectile dysfunction. A harder seat and a more athletic riding position can damage nerves and compress arteries. You may want to ride a bicycle in a relaxed riding position on a well-padded saddle to keep your penis performance intact. Padded riding pants add further protection so if you are a regular on the saddle, pad up well.