Human embryonic stem cell research rules unveiled by the Obama Administration may prevent federal funding of more cells than the old rules, suggests one report. In April, the National Institutes of Health unveiled draft rules allowing federal funding of stem cell research on tissues derived from fertility clinic embryos freely donated for research with extensive "informed consent" notification of the donors.

"Few existing cell lines would meet," those informed consent rules, says attorney Patrick Taylor of Harvard Medical School, in the current Cell Stem Cell journal, including many cell lines, or families, among those previously approved for funding by the Bush administration. Bush administration rules had limited support to human embryonic stem cell families cultured before Aug. 9, 2001.