Britain: Women having fertility treatment should be given the option to donate for research any extra eggs they do not use, the head of the first European team to clone a human embryo believes.
Dr Miodrag Stojkovic, of Newcastle University, said one of the greatest obstacles to stem cell research - which could lead to cures for conditions such as diabetes, cancer and Parkinson's - was obtaining fresh eggs.
"What we are using are eggs which are usually discarded. The development potential is not the same as fresh eggs," said Dr Stojkovic, a stem cell expert from Serbia who has also worked in Germany.
He called for a system of consent, like that for organ donors, to allow women to donate extra eggs from fertility treatment for research. Stem cells are master cells that have the ability to transform themselves into other cells and tissue. Human eggs are used to create cloned embryos, from which embryonic stem cells can be extracted.
Scientists are studying how to manipulate stem cells to treat a variety of diseases. The eggs currently available to them are those left over after fertility treatments, which are usually too old for successful research, he said.
Dr Stojkovic described a time window of up to an hour after eggs are collected in which their successful manipulation for stem cell research is most likely. "Sometimes women produce as many as 30 eggs, but the pregnancy rate does not change if you only use 10, 12 or even 20 eggs. We want to use the extra eggs prior to fertility treatment."
The British Fertility Society, which groups together medical researchers working in the field, did not object to his idea, but questioned the way a patient's consent would be asked.
"There's a danger of making just a tick-box, where patients do not consider their options properly. Patients need access to all the proper information," society spokesman Allan Pacey said.
Dr Stojkovic and his team announced last week it had cloned a human embryo, making them the first European group to do so. Scientists at Seoul National University in South Korea have also cloned human embryos.
Opponents of the research consider destroying cloned embryos for their stem cells as ending a potential human life.
But Dr Stojkovic emphasised that none of the embryos had the potential to go on to form a baby, and that the genetic material used in the process would have been discarded anyway.
"We are using material that is surplus, that is donated by people," he said. "For me as a scientist it's always more ethical to try to help people who are already with us. Why throw something in the rubbish bin when you can use it for the derivation of stem cells?" The scientists now plan to grow stem cells tailored to treat specific diseases by using a patient's genetic material to create the cloned embryo.
The South Korean scientists announced last week they had already achieved that.