The Government's fertility watchdog has approved "in principle" the creation of human-animal hybrid embryos that scientists insist will help them to develop new treatments for illnesses such as Parkinson's and motor neurone disease.
The Human Fertilisation and Embryology Authority (HFEA) cleared the way yesterday for its experts to consider licence applications from scientists wanting to combine the genetic material of human cells with animal eggs in order to create a new type of embryonic stem cell for research into debilitating disorders.
The authority emphasised its decision to consider so-called cytoplasmic hybrid research was not a total green light for the creation of human-animal embryos and each application for a research licence will be considered on its own merits.
"Having looked at all the evidence, the authority has decided there is no fundamental reason to prevent cytoplasmic hybrid research," the HFEA said.
"However, public opinion is very finely divided with people generally opposed to this research unless it is tightly regulated and it is likely to lead to scientific or medical advancements," it said.
Last November, the HFEA received two applications for research licences to carry out the cloning of animal eggs which have had 99 per cent of their genetic material removed and replaced with a full complement of human chromosomes. The resulting embryos will be almost entirely human but still part-animal.
As a result of public concerns about the technique, which were raised in a Government White Paper, the authority decided to conduct a full public consultation to decide whether it should even consider such licence applications.
The consultation involved public surveys and opinion polls. It found that most of the public were in favour of the technique once they had been properly informed about what it involves and shown the potential benefits in terms of the treatment of serious diseases.
"In general, people who do not fundamentally oppose embryo research are prepared to accept that human-animal research may have some value," The HFEA said. "But there is a clear demand from people to know more about what researchers are doing and their plans for future work, highlighting a need for better communication about science and research from both the scientific community and ourselves as regulator," it added.
Stephen Minger, director of the stem cell biology laboratory at King's College London, and one of the scientists applying for a research licence, welcomed the HFEA decision.
"It is gratifying to see that the HFEA has listened to the broader scientific and bioethical arguments. We applaud the HFEA for its decision and look forward to the decision from the licensing committee on our applications in November," Dr Minger said.
Lyle Armstrong of the Institute for Human Genetics in Newcastle, who has also applied for a research licence, said the decision was good news for British science as it would lead to new developments that could benefit everyone.
But the decision also sparked anger. David King, director of Human Genetics Alert, said: "It is very disappointing, but comes as no surprise, since the HFEA can never say no to scientists. These experiments are scientifically useless and morally very problematic. The research lobby has distorted the scientific facts in order to defuse criticism."
Dr King said the HFEA had ignored strong public opposition to such research. "People's objections to violating the integrity of nature in this way are perfectly rational, and the science establishment ignores and ridicules them at its own peril," he said.