IVF pioneer Professor Robert Winston has slammed fertility clinics for playing confidence tricks on women over egg-freezing. The procedure does not necessarily guarantee a baby.
He said doctors had no business encouraging women to sign up for freezing their eggs with the hope that the eggs could be fertilized on some later day.
He added that clinics offering social freezing should be restricted until more research is carried out.
'The whole thing is a bit of a confidence trick. If a woman goes for egg freezing and produces six to 10 eggs that's a dangerous quantity.
'It will be a result of hyper-stimulation, which increases the risk of chromosome defects. Then say all the eggs freeze and half then fertilise (after thawing) then the chance of getting one or two viable embryos is not guaranteed.
His comments were in response to a call from experts for egg freezing to be made more widely available.
Scientists at the annual meeting of the European Society for Human Reproduction and Embryology said it must be an option as more women postpone childbearing.
But then the chance of conceiving using frozen eggs is only about six per cent, according to the Royal College of Obstetricians and Gynaecologists and the British Fertility Society.
Yet the number of women putting their fertility 'on ice' to pursue a career or find the right partner has more than doubled.
At least 41 clinics now offer egg freezing which involves conventional IVF, egg extraction, freezing and then storage until the patient is ready to become pregnant.
The treatment was developed for cancer patients wanting to preserve their fertility because chemotherapy destroys eggs.
There are also concerns that not enough research has been carried out into the long-term health impacts on children born as a result of a frozen egg.
Lord Winston remarked, 'There's no child aged 30 from egg-freezing, so how do we know it's safe? The concern is the long-term genetic effects. There's considerable evidence that environmental changes in embryo development may affect humans in later life.
'In my view it's irresponsible (for clinics) to egg freeze until long-term animal research has been done.'