Young people 'experimenting more in bed'
Young people are taking part in a wider range of sexual practices, including anal sex, with opposite sex partners, research reveals.
Experts looked at responses to a national sex survey that has been carried out every 10 years since 1990 in the UK.
More than one in 10 millennial teenagers said they had tried anal sex by the age of 18.
By the age of 22 to 24, three in every 10 said they had tried it.
Vaginal and oral sex are still the most common types of sexual activity between young men and women, however.
The age that young people start having sex - vaginal, anal or oral - has not changed much in recent decades.
In the most recent survey, it was 16.
While the study in the Journal of Adolescent Health shows what types of sex people are having, it doesn't shed light on why preferences are changing.
Experts can only speculate, but say society has become more accepting and less judgemental about sexual experimentation.
Breaking down taboos
Kaye Wellings, senior author and professor of sexual and reproductive health at the London School of Hygiene & Tropical Medicine, said: "The changes in practices we see here are consistent with the widening of other aspects of young people's sexual experience, and are perhaps not surprising given the rapidly changing social context and the ever-increasing number of influences on sexual behaviour."
Prof Cynthia Graham is a professor in sexual and reproductive health at the University of Southampton.
She said the internet and media might have played a role in breaking down sexual taboos.
"The internet means people can easily find and see things that they would not have been able to in the past.
"Anal sex is still pretty stigmatised, but attitudes appear to be changing. We know society has become more accepting of things like same sex behaviour overall. But there's very little research out there about anal sex and motivation."
She said more studies were needed to inform sex education and equip young people with the information they need for their sexual health.