British scientists have for the first time been given permission to take fresh, viable eggs from women undergoing fertility treatment in order to create cloned human embryos for stem-cell research.

In return for donating some of their eggs, the women will be offered free fertility treatment under an "egg-sharing" scheme that is already used to help poorer couples have their own babies.

Egg sharing usually involves poorer women donating some of their eggs to wealthier couples who need them for fertility treatment. In return, the wealthier couple pays for the poorer couple's IVF treatment.

Now the Human Fertilisation and Embryology Authority (HFEA) is allowing the North East England Stem Cell Institute to extend the scheme to couples who volunteer to donate some of their eggs for cloning research.

The institute, a collaboration between Newcastle and Durham Universities and the NHS, can now fund the fertility treatment of women who will, in return, donate two out of 12 of their eggs for the stem cell research.

Alison Murdoch, professor of reproductive medicine at Newcastle University, said the scheme should provide scientists with a source of fresh eggs for stem-cell research using cell nuclear replacement - therapeutic cloning. "Egg sharing, when someone pays for someone else's treatment, has already been approved by the HFEA. What's different with this is that the eggs will go to research, not to another woman," she said.

Scientists at the institute have already extracted stem cells from one cloned human embryo that was made from spare "failed-to- fertilise" eggs left over from fertility treatment.

However, those eggs are of poor quality and the success rate for creating cloned embryos was extremely low. The scientists would like access to a source of good-quality fresh eggs from younger women to improve the chances of creating cloned human embryos for stem cell studies.

"Volunteers have been essential to research for many years and this is another way of engaging volunteers in a research project," Professor Murdoch said.

"All patients involved in egg sharing need IVF treatment to help them have a baby. We are helping them have treatment they may not otherwise be able to afford.

"There is no additional physical risk to the woman as a result of egg sharing," she added.

The Newcastle institute had asked the HFEA for permission to use eggs donated by women not undergoing fertility treatment but that was turned down. The HFEA announced yesterday that it was to review the rules on that issue, via a public consultation.