French women are becoming increasingly assertive in their sexual habits, while one-in-five younger French men "has no interest in sex", according to one of the most comprehensive surveys of the nation's love lives.

Women now have more than twice as many partners as they did in the 1970s, according to the study by the French Aids research agency, which is backed by the government.

The proportion of French women who claim to have had only one partner has dropped from 68 per cent in 1970, to 43 per cent in 1992 and 34 per cent in 2006. A woman's average number of partners has risen from under two in 1970 to over five today, while a man's has remained the same for four decades, almost 13.

One of the more surprising findings was that one-in-five French men aged between 18 and 24 "manifests no interest in sexuality", while abstinence rates for men under 35 was twice as high as for women.