In a massive breakthrough, human eggs have been fully grown in a lab in a world first.
Experts removed fledgling egg cells from ovary tissue and grew them to the point where they were ready for fertilisation.
This could pave the way for a new era of fertility treatments offering hope to women in danger of being left infertile from treatments such as chemotherapy.
While researchers have previously matured human eggs from a late stage of development, this is the first time a human egg has been developed in a lab from its earliest stage to full maturity.
The University of Edinburgh academics will now look at whether they can be fertilised.
Speaking about the breakthrough, lead author of the study, Prof Evelyn Telfer said, “Being able to fully develop human eggs in the lab could widen the scope of fertility treatments.”
Some cancer patients currently have a piece of their ovary removed before treatment and re-implanted later. However, there is a risk this re-introduces the disease.
Women undergoing premature menopause – which can strike in their 20s – could also benefit. These women may still have egg cells that could be developed in the laboratory.
Professor Telfer said it was unlikely that it would be of much benefit for women undergoing a menopause at the normal stage between 45-55 as they would no longer have egg cells that could be used. Experts said that much more work was needed to ensure the process was safe for humans.