by Karen Kaplan Times Staff Writer

All human embryonic stem cell lines approved for use in federally funded research are contaminated with a foreign molecule from mice that may make them risky for use in medical therapies, according to a study released Sunday....read on

The finding is a setback to the Bush administration's controversial policy that provides federal funding only for research using embryonic stem cell lines that were created before August 2001. Evidence that all such lines are contaminated supports long-standing concerns among researchers that the lines eligible for federal money are insufficient to propel research forward.