Why aren't young people having sex any more?

Sexual activity in young people is on the decline, but why? And what's more, should we be worried about what this means for society and the future of the human race? The comedy film was released in 1973 with a largely youthful cast and one too many double entendres. Half a century later, that title seems more apt than ever, at least among the younger members of society. Over the past few decades, sex appears to have been on the decline among teenagers and young adults - but it's not just happening in Britain . In the US in 2010, 12 per cent of 18 to 29-year-olds reported not having had sex in the past year, according to the General Social Survey, a long-running sociological survey.