The legal approval of cloning experiments - for example, to produce healthy organ tissue for transplantation - could lead to fierce competition for human donor oocytes, according to English physicians. However, there are already bottlenecks in donor egg cells for infertile couples, as their needs increase by 20 to 25 percent every year.

There are already too few volunteers donating eggs, says Tony Rutherford of Leeds General Infirmary, and the waiting lists are getting longer and longer. On top of that, you might want to allow limited cloning attempts, as in England.

To produce healthy replacement tissues for humans, scientists need stem cells that they extract from embryo clones. And for the embryos they need both oocytes and very young embryos. However, there may be a way out of the misery: Researchers are currently looking for ways to extract human egg cells in the test tube from ovarian tissue. (BBC)

Frieder Graef

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