Penis size - Sexual health. Some men go to extreme lengths to try to increase the size of their penis. Research has found the average erect penis size varies from around 13cm to 18cm (5in to 7in).
A visual guide to some penis problems including herpes, balanitis and genital warts.
5 penis facts - Sexual health. There are no bones in the penis, but the tubes that fill with blood during an erection can burst. On average, a healthy man has 3 to 5 erections during a full night's sleep, with each erection lasting 25 to 35 minutes.