US Senate Democrats have attempted to inject some life into an ongoing campaign to allow federal funding of embryonic research with a letter to Majority Leader Bill Frist asking him to add stem cells to a list of health-related issues due for debate next week.

The US House of Representatives last year passed a bill allowing research using 400,000 frozen embryos created for in-vitro fertilisation treatment, most of which face destruction. It has not, however, been passed by the Senate, and President Bush promised to personally veto it, declaring: "I've made it very clear to the Congress that the use of federal money, taxpayers' money, to promote science which destroys life in order to save life - I'm against that. And therefore if the bill does that, I will veto it."

Nonetheless, there is some hope for the stalled bill, Reuters notes. Frist, a Tennessee Republican, surprisingly defected to the pro-research camp last year, and is reportedly keen for it to advance. Although the Democrat petition, signed by Democratic leader Harry Reid of Nevada and stem cell bill co-sponsor Tom Harkin of Iowa - among others - carries no Republican signatures, "aides say some Republican backers of stem cell research are also eager for Frist to act".

The bill's supporters also boast some heavyweight Hollywood backing. Parkison's disease sufferer Michael J Fox said after the legislation was passed by the House of Representatives that Bush "has an opportunity to do something fantastic for the world". Harry Reid added: "President Bush has made the wrong choice, putting politics ahead of safe, responsible science."

And, to underscore the ideological brouhaha the issue has provoked, California Democrat Dianne Feinstein described some of the bill's opponents as "people who want to obfuscate this issue", who were motivated "more by ideological concerns related to abortion". ®