Today's young people are the least promiscuous generation since the 1920s, an academic study suggests.

Researchers who analysed findings from a long-running social survey from the US found that those now in their early 20s are almost three times as likely not to be sexually active as their parents’ generation.

The authors concluded that, contrary to the popular assumption, those who came of age in the era of online dating apps such as Tinder are less prone to casual encounters than their predecessors.