The fertility regulator agreed in principle today that British scientists should be able to create human-animal embryos.
The Human Fertilisation and Embryology Authority (HFEA) agreed to the controversial proposal, which scientists say will pave the way for therapies for diseases such as Alzheimer's and Parkinson's.
The positive decision from the HFEA means applications from scientists at King's College London and Newcastle University can now be appraised by a licence committee, probably in November.
A consultation paper published by the HFEA earlier this week showed that the public was mostly "at ease" with the proposals once the full research implications had been explained.
Researchers want to create hybrid embryos known as cytoplasmic embryos by merging human cells with animal eggs.
In May, the Government published the Human Tissue and Embryos Bill, which proposed a regulation-making power that could lead to the creation of cytoplasmic embryos.
Such embryos are more than 99% human, with an animal component representing around 0.1%.
The embryos are made using eggs from rabbits or cows and genetic material from human donors.
Scientists say they could provide them with a plentiful supply of stem cells for studies into new treatments.
The research involves transferring nuclei containing DNA from human cells, such as skin cells, to animal eggs that have had almost all their genetic information removed.
A certain amount of animal DNA remains in the mitochondria - tiny rod-like power plants that sit outside the nucleus and supply energy.
Stem cells, which have the potential to become different kinds of tissue, are then grown in the laboratory.
At present, scientists have to rely on human eggs left over from fertility treatment, but they are in short supply and are not always good quality.
Some religious and pro-life groups have objected to the proposals.
Some opposed mixing human and animal material on ethical grounds while others disagree with creating embryos that are destined to be destroyed.
The HFEA's decision was welcomed by Liberal Democrat science spokesman Dr Evan Harris, who has also co-ordinated the campaign of scientific groups to allow hybrid embryo research.
He said: "This is good news for patients, the public and UK science.
"Our top-class researchers can now proceed with their applications to conduct this world-leading research.
"The message to the Government is also clear - that they should stop trying to use legislation to block some forms of hybrid embryo research and instead allow the HFEA to consider each application on its merits."Reuse content