Later this month, MPs will be allowed a free vote on whether to amend the existing law on human embryo research in order to allow scientists to investigate the potential medical benefits of embryonic stem cells. These cells, which possess the ability to develop into any of the 200 or more specialised tissues of the body, promise to revolutionise medicine in the 21st century. They could allow human tissues, and possibly even organs, to be grown in the laboratory for transplant surgery.
Furthermore, by applying the latest advances in cloning technology, it may one day be possible to take a skin cell of a patient, extract the nucleus and use it to create a cloned embryo of that person in order to extract embryonic stem cells that are an exact tissue match. It would effectively mean that doctors of the future could call upon a person's own bank of tissues - or even organs - for future transplant operations that carry no risk of organ rejection.
The great disadvantage of existing transplants is that they require donors, who are in short supply. Another problem is that they almost invariably require someone to die in order than another might live.
The shortage of supply, and the morbid nature of the donation, has frequently fed the imagination of science fiction writers. The Eighties cult film Coma, for instance, portrayed a future scenario where the near-dead are kept in suspended animation until the day their organs are required by a wealthy few, who buy into a private medical system bartering on an international market for hearts, lungs, kidneys and livers.
The development of human embryonic stem cells promises to end the horrors - real and imaginary - of supply and demand in the transplant field. If existing research on animal stem cells and cloning technology proves to be applicable to humans, the implications will be profound.
Professor Martin Gardner, who chaired a Royal Society working party on stem cells and human embryo cloning, estimates that up to one in ten of the population could benefit from the technology, provided it is permitted by Parliament. "If you think of the whole range of diseases of the young and old it is possibly up to 10 per cent of the population that could benefit from stem-cell therapy. That's not a totally unrealistic figure," says Professor Gardner.
"Members of both Houses should accept that this research on early embryos is scientifically necessary if we are to ensure that patients benefit from the full range of potential treatments as quickly as possible. Embryo research is very strictly regulated in the UK and we believe an extension of the present law to allow studies on stem-cell therapies is highly desirable."
As the current legislation stands it is not possible for scientists to use cells from a human embryo unless the embryo is less than 14 days old and the cells are used for one of five purposes. These are:
n promoting advances in the treatment of infertility
n increasing knowledge about the cause of congenital disease
n increasing knowledge about the causes of miscarriage
n developing more effective techniques in contraception
n developing methods for detecting the presence of gene or chromosome abnormalities in embryos before implantation into the womb.
When the Human Fertilisation and Embryology Authority and the Human Genetics Advisory Commission conducted a joint investigation into the issues raised by stem-cell research they proposed the addition of two extra purposes, which is effectively what MPs will vote on. These are:
n developing methods of therapy for mitochondrial diseases
n developing methods of therapy for diseased or damaged tissues or organs.
The first deals with the problem of rare genetic conditions carried by the mitochondria in the cytoplasm of the cell, the part outside the central nucleus. It should be possible to cure these mitochondrial diseases by transferring the nucleus of an affected woman's unfertilised egg into the empty, "enucleated" egg of a healthy woman. The unfertilised egg created by the process, known as cell nuclear replacement, can then be fertilised in the normal way and the resulting embryo implanted into the womb.
This technique does not involve meddling with a fertilised egg and has not led to the same ethical concerns as the second proposal. The suggestion that cells of embryos less than 14 days old can be extracted for general medical use is expected to generate heated debate. Not only does it raise the spectre of using, or some might say "farming", embryos for their tissues, it would also permit scientists to create cloned human embryos for "therapeutic" purposes.
Three leading scientific bodies this week briefed MPs and peers about the technical and ethical issues surrounding embryonic stem- cell research and therapeutic cloning. The Medical Research Council, the Royal Society and the Nuffield Council on Bioethics warned politicians that not only would many patients stand to suffer, but Britain would lose its leading scientific role if this sort of research is prohibited.
"The impact on scientists working in this area could be to see what by any standards are largely British initiatives go to scientists in other countries," Professor Gardner says. "What you can be absolutely sure of is that this work will go ahead in other countries."
At the centre of the discussion is the moral status of the embryo. Members of the pro-life, anti-abortion lobby believe that the embryo is a person, or at least a potential person with certain rights, namely the right to life and the right not to be used as a means to an end. They believe it is not morally permissible to remove cells from an embryo, regardless of whether these cells are used to benefit another person.
The issues were discussed at length in the early Eighties by the Warnock Committee prior to the Tory government's implementation of the Human Fertilisation and Embryology Act. Parliament accepted that embryo research is morally acceptable for specific purposes, provided it is limited to the 14 days following fertilisation, before the development of the "primitive streak", the cells that are recognised as the progenitor nerve tissue of the future foetus.
When the Nuffield Council on Bioethics returned to the subject in its discussion paper on stem-cell therapy, it too came to the same conclusion: "A donated embryo has been created with a view to implantation in the uterus. Once it is not implanted, it no longer has a future and, in the normal course of events it will be allowed to perish or to be donated for research," the Council says in its report.
"We consider that the removal and cultivation of cells from such an embryo does not indicate lack of respect for the embryo. Indeed, such a process could be regarded as being analogous to tissue donation," the Council points out.
"Research into potential therapies is not qualitatively different from research into diagnostic methods of reproduction. Neither benefits the embryo upon which research is conducted but both may be of benefit to people in the future. Each form of research involves using the embryo as a means to an end but, since we accept the morality of doing so in relation to currently authorised embryo research, there seems to be no good reason to disallow research on the embryo where the aim of the research is to develop therapies for others," it says.
But this is not the only ethical dilemma that will be discussed in Parliament this month. By permitting the generation of embryos by cell nuclear replacement and allowing them to develop for up to 14 days, an important precedent will be set in human cloning. It will effectively mean that one of the great technical barriers to reproductive cloning will be shown to be surmountable.
Some have seen this as the thin end of a wedge that will lever open the door to the birth of cloned children. The Nuffield Council on Bioethics accepts that this is a genuine fear but believes the potential medical benefits outweigh any risks. Like all of those in favour of the proposals being tabled, the Council would like to re- affirm its view that implanting a cloned embryo into the womb would be wrong, especially if that embryo is allowed to develop to a point where it could be aborted and its organs used.
It is a reaffirmation that is unlikely to persuade the diehards who are against the research. With the support of the Chief Medical Officer, the Government and the vast majority of the medical establishment, it will be hard for MPs to vote against the proposals to extend the law on human embryo research. Hard, but not impossible.…