“I am disappointed the leadership of Congress recycled an old bill that would simply overturn our country’s carefully balanced policy on embryonic stem cell research,” Mr. Bush said in a statement. “If this bill were to become law, American taxpayers would for the first time in our history be compelled to support the deliberate destruction of human embryos. Crossing that line would be a grave mistake.”

Critics of the legislation said taxpayer dollars should not be used to increase spending on embryonic stem cell research, particularly in the wake of a new scientific advance reported Wednesday in which biologists believe they can use skin to generate new heart, liver or kidney cells. Such a technique, if proven successful, could sidestep the ethical debates surrounding stem cell research.

Throughout the Congressional debate, several Republicans who oppose the legislation seized upon reports of the new scientific advance.

“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 Pitts, a Pennsylvania Republican, holding up a front-page newspaper account of the scientific discovery. “These have all of the potential and none of the controversy.”

While those who support increasing the federal financing of embryonic stem cell research also hailed the development, they said such advances should not replace expanding research to press for a litany of diseases, including Alzheimer’s and juvenile diabetes.