There does appear to be some connection between cycling and erectile dysfunction, but you are unlikely to be affected unless you spend several hours a day on a bicycle.
A bicycle saddle can put pressure on the nerves and blood vessels that are involved in getting and maintaining an erection. So, if you spend significant time sat on a bicycle saddle, you may damage these nerves and blood vessels, contributing to erectile dysfunction.
Other than the duration of cycling, several factors may also affect your risk of developing erectile dysfunction. Some saddle designs, greater intensity of cycling and a higher weight can put more pressure on the nerves and blood vessels so could increase your chances of developing cycling-related erectile dysfunction. The risk of erectile dysfunction caused by cycling is also thought to correlate with age.
When cycling for a long period of time, the pressure and reduced blood flow could cause pain, numbness or tingling sensations around the perineum (the skin between the scrotum and the anus). This is a good indicator that you are putting too much pressure on these areas and you should make some changes to prevent any lasting damage. If you cycle regularly and experience erectile dysfunction, be aware of the abnormal sensations you may feel when cycling and make adjustments to avoid these.