It appears you're onto something with the erectile dysfunction. Apparently however, it's not that common and you can get seats that minimise the issue.

http://bicyclehabitat.com/articles/saddle-seats-and-erectile... http://sportsmedicine.about.com/od/cyclingworkouts/a/BikingI... http://www.webmd.com/erectile-dysfunction/news/20050825/stud...