Why I ... think that alternatives to therapeutic cloning should also be explored

Richard Gardner. Henry Dale research professor of the Royal Society in the zoology department, Oxford University

Chair of Royal Society working group on therapeutic cloning

7While I believe that scientists should be able to explore therapeutic cloning as a way to grow organs and tissues for human transplant operations, it is important that it is not regarded as the only possible way forward.

If the government sets up a bank of frozen human stem cells on the lines of the blood transfusion service, stem cells could be used as a therapy to prevent the many injuries and ravages of diseases. A patient in need of a liver transplant, for example, would not need to wait for someone with a healthy and hopefully well-matched liver to die.

Harvesting stem cells from cloned embryos involves invasive surgery and requires parental consent. But there are other sources, such as the umbilical cord and placenta, which are naturally discarded after the baby is born. The procedure would be less emotive and invasive. Other parts of the body, such as skin cells, may also prove to be a useful source. Recent studies have found that adult stem cells are more common than realised, although they appear to have a shorter lifespan than embryonic cells.

There is a naive notion that stem cells are immortal, but extensive experience with these cells in mice suggests that is not the case. There is the idea that the older a cell is, the less it will be able to divide.

Few people have studied stem cells in adults so we do not know their potential as an alternative to embryonic cells. As it took more than 400 eggs to clone Dolly the sheep, therapeutic cloning can be incredibly inefficient. It may be that a large number of adult nuclei cannot be reprogrammed, so we will still need aborted foetuses and unused IVF embryos.

But there are a lot of questions about therapeutic cloning and embryonic stem cells should not be trumpeted as the only answer. We need to look openly at this issue on all fronts.

Interview by Jennifer Currie

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