Old Cells Learn New Tricks
Since their discovery in 1998, human embryonic stem cells have raised hopes that they will one day provide unlimited tissues for replacing those damaged by disease. But their source has raised ethical quandaries as well, and currently public funds cannot be spent on research on the cells in the United States. Now, researchers are considering whether adult stem cells, which have shown surprising versatility, might do everything the embryonic cell can--thereby relieving the ethical and political quandaries. The jury is not yet in on this issue, however. Both adult and embryonic stem cells have their strengths and weaknesses, and harnessing either one for medical therapies will be tough, the experts say.
