San Francisco

Governor Arnold Schwarzenegger has lent his weight to California's stem-cell initiative. Credit: R. BOWMER/AP

After months of silence, California's Republican governor, Arnold Schwarzenegger, lent his backing on Monday to the state's ballot initiative to fund embryonic stem-cell research. Supporters of the plan, on which Californians will vote in two weeks, had become increasingly optimistic that it would pass following a string of endorsements from newspapers and public figures, as well as a continuing lead in the polls. The governor's approval now adds to their confidence.

The measure, known as Proposition 71, would pump $300 million a year for a decade into the ethically charged research. Its supporters say the investment would pay large dividends both in treatments for intractable diseases and in healthcare savings for the cash-strapped state. Opponents call those claims speculative at best, and point to the ethical difficulties of taking cells from embryos that are either discards of fertility treatments or created specifically for cell harvesting.

The Proposition 71 campaign turned up the heat on 24 September with a string of 30-second television spots in which researchers, patients and celebrities such as the actor Michael J. Fox, who has Parkinson's disease, urged Californians to vote ‘yes’. “It could save the life of someone you love,” says Fox in his advert, which first aired on 14 October.

The latest Field Poll, taken just after the ads began, showed 46% of Californians for the initiative and 39% against, indicating a slight increase in its popularity since August.

Proponents have lined up a long list of supporters, including dozens of patient advocacy organizations, business groups, medical associations and Nobel laureates. Several of the state's major newspapers have also lent their support, including the Los Angeles Times, the San Francisco Chronicle and The Mercury News. The Sacramento Bee is opposed.

Although initial opposition to the measure came largely from conservatives who object to embryo research on moral grounds, a number of liberal groups are now lining up against it on the grounds that it lacks adequate ethical safeguards against financial conflicts of interest (see Nature 431, 232; 200410.1038/431232b).

“Stem-cell research needs controls and oversight. People in the progressive community have been saying that for a long time,” says Susan Fogel, campaign coordinator for the ProChoice Alliance Against Proposition 71. The group's supporters include the National Women's Health Network and the California Nurses Association.

Objectors sparred with proponents before a 300-strong audience at a symposium in San Francisco on 12 October. The symposium was sponsored by former city mayor Willie Brown's Institute of Politics and Public Service. State senator Tom McClintock, a southern California Republican, said he was opposed on fiscal grounds. “I do not understand why it is suddenly the responsibility of California, with the lowest credit rating in the nation, to fund this research,” he said.

But former secretary of state George Shultz, an influential Republican who now lives in San Francisco, countered that the state would benefit from the spending. “Basic research is very productive,” he said. Shultz added that it would encourage businesses and researchers elsewhere to “come to California, where the action is”.