The documentary series returns for 20 new programmes.

In 1992, scientists researching a drug to combat the pain of angina noticed male patients achieving erections. The drug acquired the name Viagra and became this year's chemical cause celebre, inspiring a huge black-market trade and a tidal wave of media attention. This film chronicles the search for a cure for impotence but also asks if women's sexual problems have been stampeded in the rush to attend to male concerns.