LONDON Hybrid animal-human embryos created for medical research should be viewed as human and permitted to develop into children, Roman Catholic bishops have urged the British parliament.
Scientists want to use the hybrid embryos -- known as "chimeras" after the mythical half-man, half-animal creatures -- to understand better and find cures for illnesses such as Parkinson's, Alzheimer's and cystic fibrosis.
Under draft legislation to be debated in the British parliament this year, the chimeras would have to be destroyed within 14 days and it would be against the law to implant them in a woman's womb.
But Catholic bishops of England and Wales want women to have the right to bear the chimeras, which would be more than 99 percent human, as their own children, they told a parliamentary committee examining the legislation on Tuesday.
In their submission to the committee, the bishops said:
"It should not be a crime to transfer them, or other human embryos, to the body of the woman providing the ovum, in cases where a human ovum has been used to create them."
"Such a woman is the genetic mother, or partial mother, of the embryo; should she have a change of heart and wish to carry her child to term, she should not be prevented from doing so."
Scientists, who have been pushing for approval of hybrid embryos because of a shortage of human eggs for research, said the bishops misunderstood the science.
"If we are using cow eggs, there is no woman involved," Dr Stephen Minger, stem cell researcher at Kings College in London, told Reuters on Wednesday.
Eggs from animals, such as cows or sheep, would be stripped of their nuclear and species identity, he said. Human cells would then be placed in the empty egg vessels, creating stem cell lines for research.
"Using non-human eggs is really just a pragmatic way of accelerating the pace of research," Minger said.
"And we think it is more ethically justified to use non-human eggs rather than ask women to donate for research that is still very much in its infancy."
Britain is a leading centre for stem cell research, attracting scientists with a permissive environment that allows embryo studies within strict guidelines. The government has appointed a committee of legislators to recommend the best way to allow hybrid embryo research.
The bishops said they opposed creating embryos purely for research, but wanted to minimize harm to such life once created.