Women who want to delay having children may be able to freeze their eggs using a new technique developed in Japan.
The service is seen as a way to delay motherhood
Two of Britain's leading fertility clinics will begin egg-freezing services later this month.
The technique - called vitrification - involves removing water from the eggs and freezing them in liquid nitrogen.
But Dr Allan Pacey from the British Fertility Society urged caution and told the BBC the studies were too few to ensure big success rates for women.
The two leading fertility clinics told the Sunday Times the higher success rates of the new technique means they are justified in offering the service.
Previously it was thought too risky to allow women to freeze eggs, as they could have become too damaged to use.
Until now egg freezing has mainly been restricted to cancer patients whose eggs may be damaged by chemotherapy. These programmes will offer the service on a commercial basis.
The two clinics now believe the breakthrough means it is no longer unethical to prescribe this treatment to healthy women who wish to postpone motherhood for social reasons.
They say that when the eggs are thawed they are in almost as good a condition as before being frozen.
Professor Gedis Grudzinskas, medical director of the Bridge Fertility Centre, the second clinic named in the Sunday Times, told the BBC: "It (success rate) is a lot higher than if women wanted to defer having their children to their late 30s when pregnancy rates themselves are lower and other problems can arise."
Such problems were the risk of down syndrome in a child and miscarriage for older women, he added.
Earlier he told the Sunday Times: "The contraceptive pill gave women more choice about when they started their families. Egg freezing now gives women the chance to delay having children until the time that is right for them."
Dr Simon Fishel, managing director of Care Fertility, which intends to offer the programme, told the Sunday Times that the new technique "now made it ethical to offer the treatment to all women".
Care Fertility has 10 clinics across Britain.
But Dr Allan Pacey from the British Fertility Society told BBC News 24 he thought more research was needed, and he was concerned women may think they could preserve motherhood.
"Egg freezing has been problematic," he said.
"It's not worked terribly well historically and whilst vitrification is proving in laboratory studies to be reasonably good, meaning when the eggs are thawed that they're viable, there are too few studies, I think, yet to say whether or not this will actually translate into big success rates for women."