The US Senate has voted to lift restrictions on the federal funding of embryonic stem cell research but the majority is not big enough to prevent President George W Bush from vetoing the legislation.

The Senate, which is dominated by the Democratic Party, voted 63-34 in favour of extending funding but that falls shy of the two-thirds needed to override a promised veto from the president who introduced the ban in August 2001. The US Congress passed a law last year lifting the prohibition but Mr Bush issued the first (and only at this stage) veto of his presidency to kill the bill. Congress (which is also dominated by the Democrats) will vote again on the issue in the coming weeks and is likely to follow the line of the Senate but it is not expected to be able to garner enough votes to override any veto.

President Bush's stance certainly has not softened and he issued a statement after the Senate vote saying the proposed legal change “is very similar to legislation I vetoed last year. This bill crosses a moral line that I and many others find troubling. If it advances all the way through Congress to my desk, I will veto it.”

Senator Tom Harkin, a Democrat and leading sponsor of the legislation, said he hoped the president may think again. “I urge him to reconsider this bill and sign it,” he stated, before adding that it was necessary to “unleash America's scientists.''

A second proposal to the Senate, sponsored by Minnesota Republican Senator Norm Coleman, passed 70-28, which would promote research into developing stem-cell lines that will not require the destruction of potentially viable human embryos.

Sen Coleman urged its approval as a path around the ethical issues on stem-cell research that has divided US society so that federal funds could be used to support new studies without undoing President Bush's ban or provoking another veto. “Scientific research should be something that we as a society can embrace,'' he added. Senator Johnny Isakson, a Georgia Republican who co- sponsored the alternative Senate proposal, said it allows “the promise of embryonic stem-cell research'' to go forward while ensuring that “ethical lines are not crossed.''