The Church of Scotland has welcomed the decision by the Human Fertilisation and Embryology Authority (HFEA) to have a full public debate and consultation on the possibility of licensing research on human-animal hybrid embryos.

The Church's General Assembly is not opposed to all research involving embryonic stem cells, but its has expressed firm opposition to research involving the creation of human-animal 'hybrid' cloned embryos.

"Christian teaching on compassion for the sick welcomes and indeed stimulates scientific research in medicine, but always within moral limits. Some experiments, no matter how medically useful, would be unethical. Research with animal-human cloned embryos would breach moral norms," said the Church of Scotland in a statement released Thursday.

"It is highly speculative scientifically, decades from any clinical application, and other methods exist to the same end. It is both unethical and unnecessary. Here is a proper limit for research," it added.

The 2006 General Assembly debated stem cells at length and accepted that the creation of cloned embryos using human eggs might be justified under very exceptional cases, for example, the isolation of diseased cells to study motor neurone disease. But the 2002 and 2006 Assemblies both rejected the use of animal eggs to create hybrid cloned embryos.

"The cross-species admixture of reproductive cells poses significant ethical concerns. Even though only one per cent of animal material is involved, it is still a form of hybridisation. Contrary to some claims by scientists, the UK law requires that a human embryo be given more respect than merely cells in a petri dish," said the Church of Scotland in a statement released Thursday.

"It is hard to see what respect is being shown in creating an embryo, purely to extract cells from it, which is both a hybrid of human and animal, and which is thereby so disrupted that it could never be viable."

The Church of Scotland also warned that creating mixed status embryos was "a line not to be crossed".

"We also hold that humans and animals, though having many similarities, are nonetheless different in more than just the biological distinctions among species," the Church of Scotland said.

"To create chimeric reproductive entities of mixed status, even if non-viable, would breach the distinction between human and animal more fundamentally than acceptable examples like a sheep expressing a single human gene in its milk, or a functioning pig kidney inside a human body.

"Here is a line not to be crossed," the Church of Scotland said, adding that it was also "unnecessary, scientifically very uncertain and potentially risky".

The Church of Scotland reaffirmed its support for the findings of the review of stem cell research by the 2000 Chief Medical Officer's committee, which formed the basis of current UK legislation. It stipulates that, "the use of eggs from a non-human species to carry a human nucleus was not a realistic or desirable solution to the lack of human eggs for research."

The HFEA has similarly concluded that the scientific community lacks clear agreement as to the need for and benefits of this science.

The Church of Scotland dismissed as "irresponsible" and "unjustified" claims that to deny such experiments would delay cures for terminal diseases.

"Delay might be a significant factor if this was a near certain therapeutic method, where animal cells alone would give the missing breakthrough. In this case, it is basic research of uncertain outcome, many years, perhaps decades, from clinical application, and about which other scientists raise substantial technical doubts."

The Church of Scotland expressed further concern over "premature expectations" about stem cell research being raised by these kinds of claims, "especially following the Korean cloning scandal," it said.