With expectations riding high that US President Barak Obama will fulfil his campaign commitment to overturn the Bush administration’s tight restrictions on human embryonic stem cell research, Senators Tom Harkin and Arlen Specter have seized the initiative by reintroducing the Stem Cell Research Enhancement Act.

The bill would allow federal funding for stem cell research using cell lines derived from excess in vitro fertilisation embryos, regardless of when these lines were generated. The same legislation was approved with bipartisan majorities in the Senate and House of Representatives during 2007 but subsequently vetoed by then President George W Bush on ethical grounds. Bush had already vetoed the Stem Cell Research and Enhancement Act of 2005 in July 2006.

An executive order passed by Bush in August 2001 severely restricted federal funding for stem cell research involving human embryos by confining it to the 21 embryonic stem cell lines then available for study. According to Harkin and Specter, these lines were grown with mouse cells, “an outdated method that raises concerns about contamination”.

Last month the Coalition for the Advancement of Medical Research (CAMR) wrote to President Obama expressing concern over media reports that an executive order lifting the current restrictions on federal funding would need to be co-ordinated with legislation.

“We strongly advise you to issue a straightforward Executive Order that simply reverses President Bush’s policy and calls on the National Institutes of Health to issue appropriate guidelines,” the CAMR said. “Follow-on legislation that codifies an Executive Order may be appropriate but, in the interest of timing and clarity of policy, the two do not need to be linked.”

Launching the revived bill, Iowa Democrat Harkin commented: “President Obama has promised to lift the restrictions on embryonic stem cell research that were put in place by President Bush, and I hope and expect that he will do so soon, but we have to make sure that the freedom to pursue this research is also protected by Federal law, not merely by an executive order that can be reversed during a future administration”.

Specter, the Republican Senator for Pennsylvania, added that the bill was “necessary to codify this important policy change so that it does not ping-pong back and forth with each successive President. A legislative fix to the current restrictions is a more complete solution to ensure that medical research is pursued with all possible haste to cure the diseases and maladies affecting Americans.”

The Stem Cell Research Enhancement Act is co-sponsored by Senators Ted Kennedy (Democrat, Massachusetts), Orrin Hatch (Republican, Utah) and Dianne Feinstein (Democrat, California).