Bush repeats stem cell veto threat

US President George Bush has restated his intention to veto any new law extending his policy on human embryonic stem cell (ES cell) research, if the Senate passes it. Current policy, set by the President on 9 August 2001, only allows state funds to be used for research on ES cell lines that were created before that date.

Many scientists complain that these cell lines are less effective than more recently created lines, as they are contaminated with the mouse feeder cells used to grow them. The Stem Cell Research Enhancement Act 2005 would, if passed, also allow funding for scientists to conduct ES cell research on embryos left over from fertility treatments and donated for research purposes. Six other bills that would extend the policy in other ways - including one that would only allow research to take place on embryos created in or before 2005 - have also been introduced to the Senate. The Stem Cell Research Enhancement Act has already passed through the US House of Representatives, but seems to have stalled in the Senate.

Last week, Bill Frist, the US Senate Majority Leader, added his support to the legislation. A Republican and a surgeon, Frist had previously supported Bush's policy and is a known opponent of abortion. But he explained his change of heart on ES cell research, saying it did not conflict with his pro-life stance, as it promotes research into medical treatments that could save lives. But the President, in a media interview, said that he still intended to veto the law. He added that he is 'confident that I have achieved the right balance between science and ethics', and that although laws can be passed by Congress, 'the prerogative to set limits on what I think is right' remains with him. He explained that the 'dilemma' that he faced was 'do I allow the destruction of life in order to advance science?', adding that he believed that ES cell research was only one of several potential ways to cure disease.

A presidential veto can be overridden if there are 67 or more votes in favour of the bill in the Senate - Senator Arlen Specter, one of the sponsors of the bill, said last week that at least 62 Senators have pledged their support. He also added that there is much public support in favour of extending the policy, to allow the 400,000 embryos currently estimated to be in frozen storage in the US to be used in research, if donated for that purpose. 'I respect the President, but my sense is that we can use research on stem cells consistent with ethics', said Specter, adding 'the alternative is either using them or throwing them away'.