WASHINGTON — Less than a year after similar legislation died in Congress, lawmakers introduced a bipartisan bill in both chambers Wednesday that would promote embryonic stem cell research to help find cures for diseases such as cancer and Alzheimer's.

The legislation would expand the number of stem cell lines derived from unused in vitro embryos that are available for federally funded research. Under the current federal policy, only stem cell lines created before Aug. 9, 2001, are eligible for federal funds, but the bill's authors said that most of the 22 available stem cell lines have been contaminated with mouse cells and are of little use to researchers.

Stem cell research has been a contentious issue for most of President Bush's first term. It has pitted advocates such as Nancy Reagan and the late actor Christopher Reeve who see the research as the best hope to cure a host of lethal diseases against opponents who say using embryos for research equates to killing human life.

Democrats and moderate Republicans have called on the president to expand the research, but he has so far refused to lift existing restrictions. Recently, some states like California have taken matters into their own hands by increasing state funding and setting up research facilities.

"One hundred million Americans touched by a disease may one day be helped by embryonic stem cell research," Rep. Michael Castle, R-Del., one of the bill's sponsors, said. "The current embryonic stem cell research policy is simply not sufficient for the scientists that conduct the research they need to do to find cures and treatments."

Castle said that the bill enjoys bipartisan support in Congress and noted a poll released Tuesday by the Civil Society Institute showing that 63 percent of Americans back embryonic stem cell research. But he acknowledged that Bush still needed to be "persuaded" to change his policy.

Last year, Castle and Rep. Diana DeGette, D-Colo., did not put a similar bill up for vote on the House floor because of concerns that the issue would interfere with the presidential campaign. Castle said the high number of co-sponsors — 156 in comparison with 25 when the bill was first introduced last year — was a reason to be optimistic for the prospects of the bill in the House.

Rep. Phil Gingrey, R-Ga., said federal funds can be used to conduct research on adult stem cells, cord blood and embryonic material from miscarriages "without destroying human life." An anti-abortion obstetrician-gynecologist, Gingrey expressed confidence the bill will not become law.

"I remain firmly opposed to changing the president's policy," he said, but "should this bill pass, I think the president would veto it."