US: Ethical concerns over the use of embryos as a source of stem cells, plentipotent cells that can change into any tissue type in the body, have proved an enormous impediment to the use of this important technology, writes Dick Ahlstrom, Science Editor
Advocates argue that it promises cures for a wide range of diseases, and so the destruction of viable but unwanted human embryos is justified. Opponents claim the unborn are being sacrificed to produce medical cures for others.
The battle lines over the issue are sharpest in the US, where powerful conservative interests lobbied the Bush administration and won concessions that block Federal funding for stem cell research.
This has forced university and private-sector researchers back on their own financial resources if they seek to pursue this research.
Now however, two new ways to derive stem cells have been described that claim to get around the ethical problem of embryo destruction.
The methods apparently do not result in the destruction of the embryo and so should pass conservative scrutiny.
Doubts about this are already being raised, however. Neither method "really quells the ethical debate", according to Dr George Daley of Harvard Medical School.
Surprisingly, one method that requires the engineering of embryonic cells as a way to make them naturally unviable and therefore incapable of growing into a human has been backed by Dr William Hurlbut, a member of President Bush's Council on Bioethics. "This established the scientific feasibility of the idea that you can obtain fully functional embryonic stem cells from an entity that is not a natural, normal embryo," he said.
Whether these methods are actually accepted as ethically sound is of considerable importance and represents much more than another conservative/liberal tussle. Researchers around the world agree that the ability to manipulate stem cells could quickly lead to remarkable new cures for diseases such as diabetes, Parkinson's and MS.
Stem cell research is racing ahead in Britain, which introduced a liberal approach for researchers who may experiment with embryos so long as they are destroyed at 14 days. Similar advances are being made in China and South Korea. Research teams in the US have been thwarted, at least in part, by the Bush-inspired ban on Federal funding for new stem cell research.
US scientists may now hope that these new methods will be accepted as ethically sound. The methods are unlikely to win over conservative support however. The method from Advanced Cell Technology Inc involves a technique already being used as a safe way to screen potential embryos for genetic diseases. It is associated with embryo destruction, however, as the test identifies embryos that will develop disease.
The Massachusetts Institute of Technology method involves engineering an embryo, leaving it impossible to implant in the uterus. It skirts around the issue that the embryo was viable before the intervention.
