I am a 35 year old male who is a light to moderate smoker and drinker. Otherwise I am in good shape, 6'0'", 150 lbs., and was given a clean bill of health at my last physical. Over the last 6 months I have been experiencing some erectile dysfunction
, usually being unable to maintain a rigid erection. I am wondering how much of this is normal for my age and/or habits? What should I do to test, treat?