HOLLYWOOD -- Backers of a stem cell proposition that appears on the November ballot in California enlisted some Hollywood star power Tuesday to pitch their case.

Proposition 71 would authorize the state to borrow $3 billion to boost stem cell research. Supporters say that research holds the potential to find effective treatment for ailments ranging from diabetes to cancer to Alzheimer's. Opponents say that potential is vastly overstated and is mostly aimed at benefiting private biotech firms.

In Los Angeles Tuesday, backers of the proposition trotted out actors Dustin Hoffman and Edward James Olmos to express their support. Hoffman said he got involved because his daughter, Allie, has a friend with juvenile diabetes.

"We learned, with Allie, how painful and humiliating and devastating this disease is," Hoffman said.

Emma Klatman also lives with the disease.

"I believe in this research because it's an uphill battle every day ... getting up in the morning, testing my blood sugar 10 to 12 times a day, using needles, counting carbohydrates ... it's just an uphill battle and I want a cure," Klatman said.

Wayne Johnson opposes Prop. 71.

"Embryonic stem cell research is the most unproven, untested area. The venture capitalists who are willing to let the taxpayers risk their money are not willing to risk their own dollars there. They let us do the research and development and they've written this thing so they get the benefits," Johnson said.

Johnson argues there is virtually no oversight for how the money is used.

The measure's chief sponsor, developer Robert Klein, whose son has juvenile diabetes, fired back.

"And George Shultz has pointed out that this is very well fiscally-designed ... George Shultz, who was OMB Director, budget director, secretary of state, a real leader in our state and the nation," Klein said.

KCRA 3 spotted Shultz having lunch Tuesday in downtown Sacramento with Gov. Arnold Schwarzenegger, who has taken no position on the stem cell measure.

A spokeswoman, when asked if Shultz was lobbying the governor, said she didn't believe the topic came up.