Human Stem Cells Created by Cloning
Breakthrough sets up showdown with induced adult lines.
It was hailed some 15 years ago as the great hope for a biomedical revolution: the use of cloning techniques to create perfectly matched tissues that would someday cure ailments ranging from diabetes to Parkinson’s disease. Since then, the approach has been enveloped in ethical debate, tainted by fraud and, in recent years, overshadowed by a competing technology. Most groups gave up long ago on the finicky core method — production of patient-specific embryonic stem cells (ESCs) from cloning. A quieter debate followed: do we still need ‘therapeutic’ cloning?