what part of riding a motorcycle would cause ED? the cold? vibration? or maybe riding a motorcycle can be better than sex?
Probably they way you sit on it, same as a bicycle seat.
With this in mind, do you think the type of motorcycle was logged in this survey?
I mean is sitting on your arse on a Harley, your taint on a Fazer, or your bollocks on a 'busa worse?
Also, how are they sure it's down to the bikes? I've had a think about this (as a bloke in my 40's), and reckon that it's more due to boredom than biking. Bikers are by nature adventurous, not happy to do the same thing day in day out for life, right? So by the time you're my age the vanilla thing just doesn't work any more.
Personally if Mrs SD doesn't dress up as Miss Whiplash, clamp my nipples with live jump leads and wrap me in clingfilm she's not getting her portion tonight!