Erectile dysfunction is when a man can't get an erection to have sex or can't keep an erection long enough to finish having sex. (It used to be called impotence). Erectile dysfunction can occur at any age, but it is more common in men older than 75 years of age.rectile dysfunction doesn't have to be a part of getting older. It's true that as you get older, you may need more stimulation (such as stroking and touching) to get an erection. You might also need more time between erections.