GO AHEAD TO CLONE HUMAN EMBRYOS

SCIENTISTS are today set to be given the legal go-ahead to clone human embryos.

The ruling will mean that pioneering medical research on human embryonic stem cells will be allowed, opening up the prospect of new treatments for a vast range of illnesses, from cancer and Alzheimer's to arthritis.

While reproductive cloning - the creationof cloned babies - will remain illegal, limited therapeutic cloning would not. This means that scientists will be able to create human embryos in the lab and "mine" them for special cells which can be used in revolutionary medical treatments.

The House of Lords Select Committee is expected to insist that stem cell research should be used only in exceptional circumstance, where licensed researchers can demonstrate there is no alternative in the search for cures.

However, even with these strict conditions the decision will be controversial. Such research is banned in the US and elsewhere and opponents will be incensed by the news that it is to go ahead here.

The select committee was set up last year to examine claims that cloning embryos - using the technique that produced Dolly the sheep - is unnecessary.

But it is believed to have rejected the argument that the same medical advances can be achieved using conventional adult cells.

Research on stem cells taken from embryos during treatment for infertility but not used should continue to be strictly regulated, and so should research on stem cells taken from adults, the committee is expected to say.

Supporters of the research believe that scientists should be allowed to use human embryos to find ways of regenerating tissues such as nerves, muscle and cartilage. As well as potentially tackling some terminal diseases, such research would increase the hopes of people with debilitating conditions such as spinal cord injuries, burns and diabetes.

But opponents, including antiabortion campaigners and the Vatican, believe equally effective treatments could be developed without cloning, using adult cells, and fear that the new step could lead to full human cloning. Peter Garrett, director of research at Life, said: "It is part of a larger effort to con the public into believing that therapeutic cloning is not cloning. The whole exercise has been a cosmetic one from start to finish."

Stem cells are the building blocks for all cell development. The stem cell can divide into identical cells for an indefinite period and it also produces all the specialised cells which are necessary for the formation of virtually all human tissue.

In the first hours and days after fertilisation, stem cells act as the main directors in cell development, constantly dividing and subdividing and 'instructing' cells to specialise - to become blood stem cells, skin stem cells or muscle stem cells, for example.

The US House of Representatives voted to ban all human cloning, including therapeutic cloning, last year. The US Senate is to debate the issue next month. Scientists there have warned of a potential 'brain drain' from the US to Britain unless President George Bush relaxes restrictions.

Cloning Q&A

What is therapeutic cloning?

Scientists would like to create human embryos in the lab and "mine" them for special cells that can be used in medical treatments. What they do is take the genetic material from a cell in an adult's body and fuse it with an empty egg cell.

With the right trigger, this new cell can then be persuaded to develop into an embryo. It is the same basic technology that gave us Dolly the sheep.

What are stem cells?

Stem cells are the "master cells" which potentially can be developed into virtually every other type of cell in the body.

They could be developed into nerve tissue, blood, heart muscle and even brain cells.

Why are they so important?

They can provide us with replacement tissue which could be implanted into humans to repair the damage caused by degenerative illnesses like heart disease.

Ultimately it might be possible to persuade stem cells to grow into complete organs.

Research would allow the creation of perfect-match tissue. At the moment, if you have a transplant, your body will try to reject the donated cells because it sees them as foreign. Doctors have to prescribe powerful antirejection drugs that patients must take for life. But the cells created through therapeutic cloning would not have this problem. But antiabortion campaigners believe equally effective treatments could be Which diseases could be fought successfully with the research?

Leukaemia is an obvious example as, with therapeutic cloning, doctors would be able to create perfectly-matched bone marrow. New nerve cells could be created and then transplanted into sufferers from Parkinson's and Alzheimer's disease. New heart muscle could repair damaged hearts.

Is there an alternative to using stem cells?

With more research, we may find that adult stem cells are just as useful and flexible, and this would negate the need for embryos.. They think it might be possible to "reprogramme" an adult cell - even one as specialised as a skin cell, for example - to become any other cell type in the body.

This sort of technology is far from being realised and would also require, in the short term, work on embryos to learn some of the secrets of how early cells are controlled.

What do opponents say?

The breakthrough research on embryonic stem cells was done on aborted foetuses and unwanted embryos from IVF treatment. Some groups argue that even the very small clump of cells being talked about here is a human life and as such is sacrosanct. They see it as outrageous that scientists should be allowed to create something which has life to discard it after "harvesting" some important cells.

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