Research published in the Lancet shows four times as many women now report same-sex experiences with other women compared to 20 years ago. While the percentage of men who report a same-sex experience has remain almost unchanged, 19% of 16-24 year-old men report that they have had anal sex with an opposite sex partner.

According to the National Survey of Sexual Attitudes and Lifestyles, women are also starting to have sex earlier in their lives and are having more sexual partners over their lifetime than a generation ago.

“We can see that the pace of change has been different for men and for women in the last decades. The gap previously seen between them has been closing,” said lead author Professor Kaye Wellings of the London School of Hygiene and Tropical Medicine.

“For some aspects of sexual behaviour, for example numbers of partners, it has narrowed, for others, such as age at first sex, it has closed and yet in other respects, such as same-sex experience, women have overtaken men,” Professor Wellings said.

“Whilst same-sex experiences have remained relatively constant among men, it has increased markedly among women. Although a minority of women have reported sexual experiences with another woman, that proportion increased from 4% in 1990 to 16% in 2010 and 2012,” she said.

Seven per cent of men have reported sexual experiences with another man. Asked whether this four-fold increase among women was real or an artefact of the survey, Professor Wellings added: “I think it’s too big to be simply an artefact of reporting. We can see signs in the media that there have been changes in the representation of women. There have been celebrities who have apparently embraced same-sex experiences. We do see women kissing together and so on.”

The latest National Survey of Sexual Attitudes and Lifestyles, carried out between 2010 and 2012, involved detailed interviews with more than 15,000 adults aged between 16 and 74 about their sexual behaviour and attitudes.

In the 16-to-24 age group, about 31% of men and 29% of women report having sex before the age of 16 years. The same age group also destroy the myth that anal sex is limited to gay men, with 19% of men reporting that they have had anal sex with an opposite sex partner.

The report also shows that attitudes towards sex are changing. In the first survey, published during the 1990s, 78% of men thought that male same-sex relationships were wrong on some level, while 76% felt the same about female same-sex relationships.

However, there is still widespread prejudice towards LGBT couples among Britain’s male population. Fifty two percent of men still think that male same-sex relationships are wrong, with 48% saying the same of female same-sex partnerships.

The increase in tolerance among women is far more marked, with the number accepting gay and lesbian relationships rising from 28% to 66%.

Earlier this month, the government rejected a call by a public health official to consider lowering the age of consent to 15 so that teenagers can have better access to sexual health advice and protections.

Writing for PinkNews.co.uk, Simon Blake, the CEO of Brook, the young people’s sexual health charity, said the age of consent should remain at 16.

However, human rights campaigner Peter Tatchell believes there is a case to be made for lowering it to 14.