More and more women in their early thirties are taking the decision to freeze their eggs with the intention of conceiving a child a decade or so later without the risk of diminished fertility due to aging or damage to eggs due to medical treatments.

Nowadays, the eggs are subjected to an 'ultra-quick' freezing process in liquid nitrogen at -196º, which avoids the damage that used to occur with the traditional method.

There are various reasons behind the trend towards prolonging fertility.  Women who have to undergo aggressive cancer treatments often freeze eggs beforehand so as to be able to conceive afterwards.  Others do so because they carry a high risk of genetic abnormalities and need to be able to select healthy embryos.  Others cite purely social reasons, i.e., they put off having children to suit their career or lifestyle.

The Valencian Infertility Institute (IVI) has launched a programme with the support of the pharmaceutical company Merck Serono, that enables patients about to undergo cancer treatments to freeze semen or eggs free of charge to use at a later date.  Thanks to this programme, 47 women and 33 men have become parents after their illnesses have been cured,

On average, a woman's fertility peaks at about 27 or 28 years of age and eggs from women of this age that are frozen have about a 90% chance of survival.