Erectile dysfunction, or ED, is the most common sex problem that men report to their doctor. It affects as many as 30 million men. ED is defined as trouble getting . Dec 7, Erectile dysfunction (ED) is a condition in which a man regularly finds it difficult to get or keep a firm erection. ED can be caused by. The symptoms and causes of erectile dysfunction (ED). ED is often a symptom of another health problem or made worse by emotional problems.