A team of scientists has been granted permission to create embryos that are part pig, part human.
The team from the University of Warwick wants to use the embryos to produce embryonic stem cells for research into heart disease.
This is the third licence to create animal-human embryos in Britain granted by the Human Fertilisation and Embryology Authority (HFEA).
Although the Human Fertilisation and Embryology Bill allows the creation of animal-human embryos, the Bill has yet to become law. It is expected to reach its final stages in the Commons soon.
The HFEA has granted licences in this area because it considers the matter to be a grey area of law which will be clarrified in their favour when the Bill becomes law.
An opinion poll conducted by ComRes for The Christian Institute showed that 60 per cent of the public believe it is wrong to create animal-human embryos for research. However, in May MPs voted by 336 to 176 to allow the practice.
Scientists want to create animal-human embryos to assist embryonic stem cell research. They hope this research will help the development of treatments for various medical conditions.
However, a decade of work using fully-human embryos has not yet produced any successful treatments and critics say the use of animal-human embryos is even less likely to succeed.
One of the Warwick scientists, Prof Justin St John, addressed the problem: “The key thing we are doing is trying to create stem cells without any animal DNA in them.
“So even though these hybrid embryos normally have a small percentage of animal DNA , we are hoping to create cells that would have human chromosomes and human mitochondrial DNA.”
He added that they need to find a way to eliminate animal DNA from the resulting cells because the “mixing of these two diverse populations of mitochondria can be detrimental to cellular function”.