How common is erectile dysfunction?

Erectile dysfunction (ED, impotence) varies in severity; some men have a total inability to achieve an , others have an inconsistent ability to achieve an , and still others can sustain only brief s. The variations in severity of erectile dysfunction make estimating its frequency difficult. Many men also are reluctant to discuss erectile dysfunction with their doctors, and thus the condition is under-diagnosed. Nevertheless, experts have estimated that erectile dysfunction affects 30 million men in the Untied States.