Urged anew by Nancy Reagan, Senate Majority Leader Bill Frist is reviving a bill to expand federal funding for embryonic stem cell research despite objections from some conservatives and a veto threat by President Bush.

The bill would permit the federal government to pay for human embryonic stem cell research, a science that carries promise in the hunt for cures to diseases that afflict millions of people.

While most polls show that about 70 percent of the public supports the bill, it has been stalled in the Senate since the House passed it last year

Social conservatives liken the research to abortion because the process of extracting stem cells from the days-old embryo results in its death. Bush, who believes the practice is immoral, has threatened to veto the legislation if it reaches his desk.

Two officials close to the developments said the former first lady, whose behind-the-scenes advocacy helped the bill win passage in the House, spoke with Frist last week and urged him to move the bill.

President Reagan died in 2004 after suffering for more than a decade from Alzheimer's disease, an ailment that scientists say that stem cell research could help relieve or cure.

Frist, R-Tenn., planned to bring up the bill Thursday as part of a three-bill package. Sen. Tom Coburn, R-Okla., intended to block the package, several Republican and Democratic officials said.

But Frist would then have the option to call for an up-or-down vote only on the House bill, a move being considered for next month, the officials said, speaking on condition of anonymity because Frist planned to bring the bills before the Senate later Thursday. They said any senator also could try to attach the measure to another bill.

A heart transplant surgeon and possible presidential candidate in 2008, Frist stunned many in his party last year by publicly announcing his support for the bill and promising a vote on it before the 109th Congress expires at the end of this year.