Embryo freezing became an option for couples having difficulties conceiving after 1984 when a team in Melbourne helped produce the world's first baby born from a frozen embryo.
Nowadays, freezing embryos is considered a standard service in most fertility clinics. It enables couples to maximise their chances of success. They can even try for a second or third child without having to undergo the painful process of egg gathering again.
In the UK, clinicians are only allowed to insert two embryos at a time. Currently, British clinics are only allowed to store embryos for five years, although this can be increased to 10 years or even longer in exceptional circumstances.
However, storage can rarely continue once a woman reaches 55. At the HARI unit in the Rotunda, a similar regime is in place. Prospective parents have to sign consent forms which also document what is to happen in case one or both of the couple dies.
Egg freezing has only become available recently. It is still a new technology and has a low success rate. However, it is offering women the possibility of saving their fertility - in the case of cancer patients - or just delaying their childbearing years.