Impotence can have emotional causes but most often it is due to a physical problem. The physical causes of impotence include diseases (such as diabetes and hypertension), injuries (such as from prostate surgery), side-effects of drugs (such as the protease inhibitors used in HIV therapy), and disorders (such as atherosclerosis) that impair blood flow in the penis. Impotence is treatable in all age groups. Treatments include psychotherapy, vacuum devices, surgery and, most often today, drug therapy.
So not only are erectile problems common, they're nothing for you or your special friend to be freaked out about. Check out the nine most common reasons that dudes sometimes can't get it up, and get ready to become the soothing voice of reason the next time the guy you're with has a hard time pitching his tent in your happy valley. Everything (and every penis) is gonna be fine!