Human embryonic stem cell (hESC) research can be a highly controversial topic. Certainly in the US, the Bush administration, along with the pro-life movement, are vehemently opposed to such research. They view hESC research as destroying innocent human life, an anathema to their beliefs. Following his ascendancy to the nation's top job in 2001, President Bush signed an executive order that restricted the use of federal funds for such research, and last month used the only veto of his six years in office to block passage of a popular bill that would redress that.
Now, details of a new technique have been published that might placate the sensibilities of some hESC critics. Traditionally, hESCs are removed from embryos when they are blastocysts, destroying them in the process. This novel procedure, developed by a group of scientists from Advanced Cell Technology and published online in Nature, involves modifying a common practice used in in vitro fertilization (IVF), that of pre-implantation genetic diagnosis (PGD). This involves removing a cell from the embryo before it even gets to the blastocyst state. Typically PGD is performed during IVF when the embryo has around ten or less cells; the cell that is removed is used to screen the embryo for genetic defects. In cases where no defects are found, the remaining cells can be implanted in the uterus, where they develop normally. So far, the children born using this procedure appear to have no health issues resulting from it.
Klimanskaya and colleagues have successfully shown that hESC cell lines can be created from this single cell removed at this early stage, and that this does not interfere with the development of the embryo, which in theory should be enough to satisfy many of the moral critics of such work. Personally, I'm not so sure. The single cell that is removed could, in theory, be used to create another life, and I think that would be enough for current critics to find objectionable. Meanwhile, over half a million embryos left over from IVF sit in freezers across the US, in limbo between the trash bin, the petri dish, or the womb.