Stem cell researchers are worried that they'll have to stop work with some of their favorite cell lines, NPR reported yesterday . Geneticist Julie Baker of Stanford University says she faces a "huge setback." Rigorous new paperwork requirements for getting a line listed in the National Institutes of Health stem cell registry—the only lines federally-funded researchers can use—have delayed the listing of several lines derived at the University of Wisconsin. A problem is that some embryos from which the lines were derived come from a fertility clinic in Israel. A spokesman for WiCell, a nonprofit group affiliated with the university says, "Without direct access to the records for these lines ourselves, we are working through the clinic overseas to obtain the additional documentation."