In this week's BioNews we report on a new study that shows it may be possible to extract healthy stem cells from abnormal human embryos. This is good news for researchers attempting to understand how embryo stem cells develop into different body tissues. It raises the possibility that visibly abnormal human embryos 'left over' after couples have undergone fertility treatment could provide a plentiful source of healthy stem cells.
It also means that the low success rates so far obtained in animal reproductive cloning experiments may not be such a problem in therapeutic cloning research. But the study, carried out on frog embryos, does not affect the ethical arguments surrounding therapeutic cloning, as some reports have claimed.
A single IVF cycle usually produces several embryos, some of visibly better 'quality' than others. The procedure involved in therapeutic cloning - SCNT (somatic cell nuclear transfer) - is similarly unpredictable, though the success rates in animal experiments have always been very low. However, any attempt to produce cloned embryos may produce healthy ones as well as abnormal ones. It seems unlikely that researchers trying to isolate stem cells would throw away healthy embryos in favour of using embryos displaying signs of abnormal development. And even if they did, throwing away healthy embryos rather than using them in research would not change their eventual fate.
But there is another reason why working only with stem cells from abnormal embryos would not solve any ethical arguments, which strikes at the heart of the debate over cloning for medical research reasons. Pro-life and religious groups who oppose embryo research hold the view that a cluster of cells no bigger than the full-stop at the end of this sentence has the same rights as a living human child or adult. They argue that no-one has the right to curtail the life of a very early human embryo, even if it were only destined to survive for a few days. In contrast, those arguing in favour of therapeutic cloning research believe it is ethically acceptable to use these embryo cells in research that may lead to new treatments for a range of incurable illnesses. This is one of the arguments that recently convinced UK politicians to give this potentially life-saving research the green light. It remains a key issue in the therapeutic cloning debate, and one that should not be skirted around.
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