Erectile Dysfunction.  Healing Impotence.  Penis Enlargement.

MedLine Plus: Erectile Dysfunction  This is a US government portal with links to many sources of valuable information on erectile dysfunction. Here is a sampling of what you'll find there:

• Sexual Dysfunction — Silence About Sexual Problems Can Hurt Relationships
• Cigarettes send male sex life up in smoke MIAMI, March 7 – Cigarette smoking significantly increases the risk of erectile dysfunction, according to a study reported today at the American Heart Association’s 43rd Annual Conference on Cardiovascular Disease Epidemiology and Prevention.
  
  Men who smoked more than 20 cigarettes daily had 60 percent higher risk of erectile dysfunction, compared to men who never smoked. The data showed a dose-related impact of smoking: the risk of erectile dysfunction was lower in men who smoked fewer cigarettes, but still increased compared to non-smokers.
• Sexual Function in Men Older than 50 Years of Age.
• Male Sexual Problems

Mayo Clinic has many articles on erectile dysfuncion: "Erectile dysfunction (ED) affects the lives of 15 million to 30 million American men and their partners. The term erectile dysfunction covers a range of disorders, including curvature of the penis during erection (Peyronie's disease), prolonged painful erection not associated with sexual desire (priapism) and premature ejaculation. But usually it refers to the inability to obtain an adequate erection for satisfactory sexual activity.... "

Here are just a few. Check the Mayo Clinic site for additional information:

• Erectile dysfunction in diabetes: Keys to prevention
• Oral medications for erectile dysfunction: Explore your options
• Intimacy and aging: Tips for sexual health and happiness
• 'Herbal Viagra': Is it safe?

Alternative Medicine for Men's Sexual Problems
 

Center for Sexual Medicine Clinical Trials

Clinical Trials for Erectile Dysfunction from ClinicalTrials.gov