Californians voted resoundingly on Tuesday to borrow $3 billion to fund stem cell research over the next 10 years, with 59 percent of the population voting to support Proposition 71. The state plans to target research for which federal money is not available, such as developing new lines of embryonic stem cells (ESC).

Funding from the California Stem Cell Research and Cures Initiative, which may total as much as $350 million per year, could dwarf other expenditures on ESC. The U.S. National Institutes of Health spent less than $25 million on the field in fiscal 2003, although it spent more than $380 million on adult stem cell research. The promise of new money might lure stem cell researchers to California. "It does create a strong gravitational pull for junior investigators and some senior investigators," says David Scadden of Massachusetts General Hospital, who co-directs the Harvard Stem Cell Institute. But he adds that the strong public endorsement of the importance of the research "certainly helps the field overall." The competition could also stimulate increased funding by other states, New Jersey for one, which initially allocated $6.5 million for a new stem cell institute in May.

A diverse coalition, including people against the research on moral grounds and those who felt that the plan was irresponsible for the financially troubled state, opposed the California initiative. But its proponents, including prominent medical researchers, raised millions of dollars to convince voters to endorse the spending to create the California Institute for Regenerative Medicine, which will oversee distribution of the funds.

Stem cells can differentiate into any other cell type and may be especially useful for treating diseases such as diabetes, Parkinson's and some heart problems in which a single cell type is defective. But although stem cells can be extracted from bone marrow, umbilical cord blood and other tissues, the most versatile cells are ESCs, taken from embryos a few days old. (The image above shows an embryo at the two-cell stage.) In 2001 President Bush authorized federal funding of ESC research, but only for work on cell lines that already existed to avoid encouraging the destruction of embryos for research. As it turns out, only 22 of those lines are actually useful and these are hard to manipulate in the lab. In addition, Scadden points out that every ESC line exhibits different characteristics and researchers need access to a wide variety of cell lines to learn which is best suited for each purpose. Another problem is that all existing ESC lines have been grown on mouse cells and may contain viruses or other material that make them unsuitable for use in humans. As a result, many stem cell scientists embrace the California initiative's potential to fill a scientific gap created by the current federal policy.