On a vote of 247 to 176, the House overwhelmingly passed the bill, with more than three dozen Republicans joining a Democratic-led effort to authorize federal support for research using stem cells from spare embryos that fertility clinics would otherwise discard. The Senate approved the legislation in April.
“Science is a gift of God to all of us and science has taken us to a place that is biblical in its power to cure,” said Speaker Nancy Pelosi, Democrat of California, arguing for the bill’s passage. “And that is the embryonic stem cell research.”
But minutes after the vote, Mr. Bush renewed his pledge to veto the proposal, which he called “a recycled old bill.” It would reprise the first veto of his presidency, which occurred last year when he rejected a similar bill passed by the Republican-controlled Congress.
“Recent scientific developments have reinforced my conviction that stem cell science can progress in ethical ways,” Mr. Bush said in a statement from Germany, where he was attending the Group of 8 meeting. “Researchers have been investigating innovative techniques that could allow doctors and scientists to produce stem cells just as versatile as those derived from human embryos, but without harming life.”
The House bill received support from 210 Democrats and 37 Republicans, 35 votes short of what would be needed to override a presidential veto; 16 Democrats joined 160 Republicans in opposing the legislation.
Several Republicans voting against the bill seized upon scientific findings reported Wednesday, in which biologists said they could use cells from ordinary, adult cells of the body, instead of stem cells. Critics of the bill also said taxpayer dollars should not be used for research on cells derived from discarded human embryos, particularly in the wake of such advances.
“How many more advancements in noncontroversial, ethical, adult stem cell research will it take before Congress decides to catch up with science?” said Representative Joseph R. Pitts, Republican of Pennsylvania, holding up a front-page newspaper account of the scientific discovery. “These have all of the potential and none of the controversy.”
Such techniques, if proven successful, could sidestep heated debates about the research. The technique described on Wednesday works only in mice and is unsuitable for humans. Scientists hope it will prove adaptable to human cells, but cannot say when that may happen.
“None of this work lessens the imperative to loosen federal and state restrictions that currently slow progress in this area,” said Dr. Sean J. Morrison, director of the Center for Stem Cell Biology at the University of Michigan.
While lawmakers who support more federal financing of embryonic stem cell research also hailed the research development, they said such advances should not stop Congress from expanding research that could lead to treatments for a litany of diseases, including Alzheimer’s and juvenile diabetes.
“We welcome these advances as we welcome all advances in ethical life-saving research,” said Representative Diana L. DeGette, a Colorado Democrat and a sponsor of the bill. “However, this new scientific research should not be used as an excuse to say that it is a substitute for embryonic stem cell research.”
Many scientists agree, saying they need to generate new lines of embryonic cells from discarded human blastocysts, or very early embryos. They also want to develop embryonic stem cells by nuclear transfer, the replacement of an egg nucleus with one from an adult cell. A major benefit of nuclear transfer would be to walk a patient’s cell back to an embryonic state so disease processes could be better understood.
“I would find it immoral to delay the research to see if egg nuclear transfer or this method gets to our goals first,” said Dr. Irving L. Weissman, a Stanford University researcher, referring to the new technique.
Democrats urged the president to change his mind and sign the legislation. Their campaign to override the expected veto began only hours after the bill was passed, with Ms. Pelosi and Senator Harry Reid of Nevada, the majority leader, staging a ceremony to send the legislation to Mr. Bush. They invited a few dozen children and adults — many of them in wheelchairs — who say they could benefit from stem cell research.
Any effort to override a veto would begin in the Senate, where the bill passed April 11 on a 63-45 vote. Even counting the three Senate Democrats who were not present for the vote, passage was one vote shy of the two-thirds majority needed to override a veto.
“I would hope that people around the president will have him understand how important this is,” Mr. Reid said. “We’re depending on the president to do the right thing.”
Representative John A. Boehner of Ohio, the Republican leader, said Democrats were trying to turn the debate into a political opportunity because they knew the president intended to veto it. After winning the majority in both houses last fall, Democrats made expanding federally financed stem cell research a priority in the new Congress.
“This is politics. This is not about expanding research,” Mr. Boehner said. “They understand clearly that the president has vetoed this bill in the past and will veto it again.”
Since 2001, when Mr. Bush issued an order prohibiting the use of federal money for research on new stem cells derived from embryos, medical research and domestic politics have been intertwined. His order limited federal financing to the handful of lines of embryonic stem cells already in existence, but researchers complained that most of those cells were damaged or inadequate.
The new legislation essentially would overturn Mr. Bush’s order. Polls suggest a wide majority of Americans support embryonic stem cell research, but many social conservatives in Congress find the use of discarded embryos unacceptable. “I believe that life begins at conception and destroying embryonic human life for the purpose of research is morally wrong,” said Representative Mike Pence, Republican of Indiana.
Others vigorously disagreed.
“Being pro-life is about more than caring for the unborn,” said Representative Christopher Murphy, Democrat of Connecticut. “It’s about caring for the living as well.”