SAN FRANCISCO -- California Gov. Arnold Schwarzenegger has endorsed a $3 billion bond measure that would fund human embryonic stem cell research.

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Schwarzenegger's position represents a break with California's Republican Party, and poses some political risk.

Schwarzenegger has said he supports the research. His father-in-law, Sargent Shriver, is in the early grips of Alzheimer's disease. Supporters of the measure say Alzheimer's could someday be treated with stem cells.

"California has always been a pioneer. We daringly led the way for the high-tech industry and now voters can help ensure we lead the way for the bio-tech industry," Schwarzenegger said Monday, The Associated Press reported.

If Proposition 71 passes, it will provide California researchers with nearly $300 million a year for 10 years but cost a total of $6 billion to pay back.

In September, actors Dustin Hoffman and Edward James Olmos expressed their support for the stem cell proposition. Hoffman said he got involved because his daughter, Allie, has a friend with juvenile diabetes.

Stem cell research has also become a presidential campaign issue this year -- a debate that got new publicity in the wake of Christopher Reeve's death.

Reeve, a quadriplegic for the last nine years of his life, was an advocate for spinal cord research. He favored looser restrictions on stem cell research, a position favored by Sen. John Kerry.

President Bush has limited federal funds for research on embryonic stem cells to lines already in existence, blocking production of new embryos for research purposes.

Earlier this week, Democratic vice presidential candidate John Edwards said Kerry's approach would mean "people like Christopher Reeve will get up out of that wheelchair and walk again."

But Senate Majority Leader Bill Frist -- a doctor -- accused Kerry and Edwards of "shamefully" using Reeve's death "to promote falsehoods and dishonesty" about Bush's position.