A dearth of marriagable men has left an “oversupply” of educated women taking desperate steps to preserve their fertility, experts say.

The first global study into egg freezing found that shortages of eligible men were the prime reason why women had attempted to take matters into their own hands.

Experts said “terrifying” demographic shifts had created a “deficit” of educated men and a growing problem of “leftover” professional women, with female graduates vastly outnumbering males in in many countries.

The study led by Yale University, involved interviews with 150 women undergoing egg freezing at eight clinics.

Researchers found that in more than 90 per cent of cases, the women were attempting to buy extra time because they could not find a partner to settle down with, amid a “dearth of educated men”.

Experts said the research bust the myth that “selfish career women” were choosing to out their fertility on ice in a bid to put their careers first.

They said sweeping social changes meant that many professional women now struggled to find a partner that felt like an equal match.

In recent decades, the gender balance at British universities has tipped dramatically.

In 1985, 45 per cent of UK students were female, but by 2000, 54 per cent were women.

This group, now in their late 30s, is finding it harder to find a man of equal status, fertility experts said. And the trend is set to steepen in future generations, they warned, with nearly six in ten current students female.

The research, presented at the European Society for Human Reproduction and Embryology conference in Geneva, was based on detailed interviews with women in the United States, and Israel. But the lead author said similar trends were likely in the UK, where women are 35 per cent more likely than men to go to university.

Prof Marcia Inhorn, Professor of Anthopolgy at Yale University, said professional women found themselves losing out in a game of “musical chairs” because there were simply too few men of the same calibre to go around.

“There is a major gap - they are literally missing men. There are not enough college graduates for them. In simple terms, this is about an oversupply of educated women,” she said.

“In China they call them ‘left over women’. It sounds cold and callous but in demographic terms this is about missing men and left over women.”

The former President of the Society for Medical Anthropology said the women interviewed in the study were highly successful, with 81 per cent having a college degree.

“These are highly educated, very successful women and one after another they were saying they couldn’t find a partner. How could it be that all these amazing, attractive intelligent women were lamenting about their ability to find a partner?” she said.

“The answer comes in the demographics - growing disparities in the education levels of men and women.

The anthropologist suggested some women might need to be prepared to compromise some of their standards in order to find love. But she suggested society should act to increase the number of men going into higher education.

“It may be about rethinking the way we approach this,” she said.

“Most women who are educated would like to have an educated partner. Traditionally women have also wanted to ‘marry up’ to go for someone more successful, financially well off.”

“Maybe women need to be prepared to be more open to the idea of a relationship with someone not as educated. But also may be we need to be doing something about our boys and young men, to get them off to a better start.”

Some women were paying a high price for feminism, she suggested.

“As a feminist I think it’s great that women are doing so well but I think there has been a cost that has been paid,” she said, warning that many had been left in “sadness and isolation”.

In some cases, the women taking part in the in-depth interviews said they would be happy to be in a relationship with someone less educated, but they felt they were “intimidating” to the men who were available.

Researchers said that until now, many commentators on egg freezing had assumed that it was being driven by a desire to preserve fertilty, while rising up the career ladder.

“I think this is an issue that has been misinterpreted so much - this idea of a selfish career woman, putting her fertility on hold,” said Prof Inhorn.

Professor Geeta Nargund, medical director of UK clinics Create Fertility, said: “It is something to celebrate that more women are going to university and getting educated but, at the same time, when it comes to starting a family it seems there is now a societal problem with these women finding men at the same level of education.

“Women tell us frequently that they are freezing their eggs because the men they meet feel threatened by their success and so unwilling to commit to starting a family together.”

Prof Adam Balen, President of the British Fertility Society, said: “We are seeing some big societal issues, in particular in some social economic groups, with young men not committing.”

One in five women in the UK is now childless by the end of their fertile life - compared to one in 10 a generation before, he said.

Last year less than 105,000 male 18-year-olds started university, compared with almost 135,000 females, UCAS figures show, with more women than men on two-thirds of courses.

The gender gap for higher education is now as large as that between rich and poor people, which was described as a “worrying inequality” by former UCAS chief executive Mary Curnock-Cook.

British fertility experts said the gulf was "terrifying". Dr Gillian Lockwood, executive director, IVI said: "It exacerbates the problem of men not wanting to 'settle down' and start a family until it's almost too late for the woman to conceive naturally.

And if she insists, he's quite likely to leave for a younger woman whose biological clock isn't ticking quite so loudly."

Her own survey of women doing “social” egg freezing found the overwhelming majority of women having their eggs frozen were doing so because they could not find a partner, or because their own partner would not commit.

Typically, it costs around £10,000 to freeze eggs and keep them in storage for 10 years in the UK.

Professor Simon Fishel, founder of Care Fertility, said: “Anthropologically we are always searching, consciously or unconsciously, for like-minded people so it is not a great leap to understand that women are looking for someone on the same level, who is university-educated or a professional.

View more!

“This problem of "missing men" is absolutely the case in many situations in the UK, but there is a wider problem behind the increasing desire for egg freezing, not least about men and women being too unaware of their biological clocks.”

“Almost all of the women in the study who employed egg freezing were heterosexual and wanted to become married mothers,” the research found. “Women lamented the ‘missing men’ in their lives, viewing egg freezing as a way to buy time while on the continuing (online) search for a committed partner.”

The study found that more than 90 per cent of those freezing their eggs were not intentionally “postponing” their fertility because of education or careers.

“Rather they were desperately ‘preserving’ their fertility beyond the natural end of their reproductive lives, because they were single without partners to marry.”

“In most cases, these women were unable to find educated men willing to commit to family life - the reflection of a growing, but little-discussed gender trend, with women increasingly outnumbering male college graduates,” the report found.