Even in death, "Superman" star Christopher Reeve (search) is promoting human embryonic stem cell research.

The paralyzed actor stars in a new TV commercial in support of a California ballot measure that would devote $3 billion to stem cell experiments. The 30-second spot was filmed about a week before Reeve died of an infection Oct. 10.

"Stem cells have already cured paralysis in animals," Reeve says, referring to work with paralyzed rats that were made to walk again after being injected with stem cells at the University of California at Irvine. "Stem cells are the future of medicine. Please support Proposition 71 (search) and stand up for those who can't."

The spot was to begin airing statewide on Friday, the day after Reeve's widow endorsed John Kerry (search) for president.

The actor was paralyzed from the neck down in a 1995 horse riding accident.

"His family and his foundation wanted the people of California to see this recently recorded message," said Kathy Lewis, chief executive of the Christopher Reeve Paralysis Foundation.

Opponents of the Nov. 2 ballot measure decried the ad.

"I think it's pretty pathetic that we are playing on the fears of those who are sick," said Jennifer Lahl, executive director of the Bay Area Center for Bioethics and Culture. "This is playing on fears that help is on the way, that cures are around the corner."

Kerry and President Bush are battling over the ethics of human embryonic stem cell research, which requires the destruction of days-old embryos. Many conservatives who believe life begins at conception oppose such research.

Bush has restricted federally funded research to about $25 million last year.

Republican Gov. Arnold Schwarzenegger broke party ranks last week and endorsed the ballot measure.

A Public Policy Institute of California poll released Thursday found that 50 percent of likely voters support the measure, with 39 percent opposed and 11 percent undecided. The poll had a margin of error of plus or minus three percentage points.