Barack Obama is poised to sign an executive order on Monday lifting restrictions on federal funding for human embryonic stem cell research. The move comes almost eight years after George W. Bush, the former president, imposed strict limits that critics said hindered medical research and hurt US science.

Stem cell research is fiercely opposed by some religious groups because it involves the destruction of human embryos. But scientists and health activists argue it could reveal treatments for conditions ranging from diabetes to Parkinson's disease. Under Mr Bush’s restrictions, funding was allowed only for a relatively small number of existing cell lines to prevent taxpayer money being used to destroy additional embryos.