By Laura Donnelly in Geneva
A dearth of eligible 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 "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 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 trying to buy extra time because they could not find a partner.
Experts said the study busted the myth that "selfish career women" were choosing to stall their fertility to prioritise their careers.
In recent decades, the gender balance at British universities has tipped. In 1985, 45 per cent of 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.
The trend is likely to steepen in future generations, they warned, with nearly six in 10 current students female.
The number of British women having their eggs frozen has tripled in five years, with around 4000 such cases in total.
The research, presented at the European Society for Human Reproduction and Embryology conference in Geneva, was based on detailed interviews with women in the US and Israel.
But the lead author said similar trends were likely in Britain, where women are 35 per cent more likely than men to go to university.
Professor Marcia Inhorn, a professor of anthropology at Yale, said: "There are not enough college graduates for them. In simple terms, this is about an oversupply of educated women. In China they call them 'leftover 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 degree.
She 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.
Professor Geeta Nargund, the medical director of Create Fertility, a clinics group, said: "Women tell us frequently that they are freezing their eggs because the men they meet feel threatened by their success and so are unwilling to commit to starting a family together."
Last year fewer than 105,000 male 18-year-olds started university, Ucas figures show, compared with almost 135,000 women.
Fertility experts said the gulf was "terrifying".
Dr Gillian Lockwood, the executive director of IVI, a fertility treatment provider, said: "It exacerbates the problem of men not wanting to 'settle down' until it's almost too late for the woman to conceive naturally."