A California state senator introduced legislation on Monday to make sure the state reaps a return on its controversial $3 billion stem cell research program.

The bill by Democratic Sen. Deborah Ortiz, who chairs the Senate Health Committee, would tighten up the Proposition 71 initiative passed by California voters in November.

Ortiz, who backed the initiative, wants to protect the state’s investment in the 10-year scientific program and bar conflicts of interest among private officials who will manage the research money.

The bill also requires public meetings of the program’s Independent Citizen’s Oversight Committee and protects women producing eggs for studies and undergoing fertility treatments.

The legislation also would make treatments developed from the research available to low-income residents and give a share of drug patent royalties to the state.

“Taxpayers and voters made a significant commitment of a large amount of funds to further this very important issue and research. It is imperative that the state see a return on its very generous investment,” a spokeswoman for Ortiz said.

Critics of the initiative have complained the research will benefit private biomedical companies and venture capitalists at taxpayers’ expense.

California is appointing members of the oversight panel and is evaluating plans for new labs and research sites.

Scientists hope to cure diseases like diabetes and Alzheimer’s by using stem cells - master cells used to generate new blood and tissue. They can come from a variety of sources, but those taken from day-old human embryos seem to have the most flexibility, although scientists agree more research is needed.

In 2001, President Bush restricted federal funding for studies involving stem cells removed from human embryos, citing ethical concerns.