Professor Robert Winston describes the physiological changes that take place in the body when a man gets an erection. A group of adolescent boys then discuss how erections can be embarrassing, and their experiences of having a wet dream.

This clip is from:
Bitesize Secondary, Science 1
First broadcast:
28 February 2008

The clip could be used as part of a sex education class, to introduce the various changes that boys go through at puberty.