In a letter to the US National Bioethics Advisory Commission, President Clinton said that he is "deeply troubled" by reports that Advanced Cell Technology of Worcester, Massachusetts, created the part-cow, part-human hybrid in an experiment three years ago.
The commission is meeting this week in Miami to discuss the ethical implications of the claims made by the company, which said it had created a 32-cell embryo by fusing the nucleus of a human skin cell with a cow's egg that had had its own nucleus removed.
Tom Murray, the director for biomedical ethics at Case Western Reserve University in Cleveland and a member of the commission, said there was some scepticism about the "chimeric embryo" from other scientists who have criticised the company for not publishing the research in a journal. "I'm surprised that anyone would have tried it. Scientists are highly sceptical because the basic ground work was not done," he said.
While President Clinton expressed concern about the "mingling of human and non-human species", his letter is more positive about the potential benefits of combining embryo and cloning technology to create human embryonic stem cells, which can be used to grow into a wide range of tissues for transplant operations.
Scientists made an important breakthrough this month in being able to isolate embryonic stem cells from human embryos.
They believe it might be possible to create stem cells of a patient by cloning and use them to treat illnesses, from Parkinson's disease to cancer.Reuse content