A man is considered to have erectile dysfunction if he regularly finds it difficult getting or keeping a firm enough erection to be able to have sex, or if it interferes with other sexual activity. Having erection trouble from time to time isn't necessarily a cause for concern. If erectile dysfunction is an ongoing issue, however, it can cause stress, affect your self-confidence and contribute to relationship problems. Problems getting or keeping an erection can also be a sign of an underlying health condition that needs treatment and a risk factor for heart disease.