‘Numerous' studies in the past appear to have shown a link between cycling and ED. The researchers admit that they 'cannot completely discount' these. But suggest their longer-term approach may allow for the benefits to the heart from cycling to be factored in. In other words, a healthy heart reduces the risk of ED even though the short-term effect of cycling for too long may be to increase it. Remember too, that compared to taking no exercise, cycling tends to protect against ED.
http://www.menshealthforum.org.uk/news/cycling-does-not-damage-your-sex-life
Bicycling is a terrific way to get from one place to another. It’s also an excellent form of exercise, providing the same health benefits as walking, jogging, swimming, and other aerobic activities. Some men and women avoid bicycling, though, because they worry that it may damage their reproductive organs and harm their sexual function.
Science supports this worry. But it mainly applies to people who cycle a lot. And it isn’t inevitable—there are many things you can do to protect your sexual health as you cycle to improve your overall health
http://www.health.harvard.edu/blog/biking-and-sex-avoid-the-vicious-cycle-201209145290
There is an association between bicycling and decreased genital sensation in competitive women bicyclists. Negative effects on sexual function and quality of life were not apparent in our young, healthy premenopausal cohort.
http://www.ncbi.nlm.nih.gov/pubmed/17100935
The frequency of impotence, numbness of the penis, hand weakness and sensory symptoms from the fingers in bicycle sport may be higher than hitherto recognized. It afflicts both experienced cyclists and novices. In some, the complaints may last up to eight months. Besides changing the hand and body position on the bike, restricting the training intensity, and taking ample pauses may also be necessary in prolonged and vigorous bicycle riding to prevent damage to peripheral nerves.