The House on Wednesday failed to override President Bush's first veto of his five-and-a-half-year administration, cast earlier in the day when he rejected a bill that would have provided more federal funding for embryonic stem cell research.

The vote, 235-193, was less than the two-thirds needed to forward the bill to the Senate for its consideration.

Click here to read President Bush's letter to the House of Representatives.

"If this bill were to become law, American taxpayers for the first time in our history would be compelled to fund the deliberate destruction of human embryos. Crossing this line would be a grave mistake and would needlessly encourage a conflict between science and ethics that can only do damage to both and harm our nation as a whole," Bush wrote in a letter to the House explaining his decision to veto the measure.

Beginning debate on the issue, House Majority Leader John Boehner of Ohio asked his colleagues to uphold the president's veto.

"The bill signed by the president today is a positive step forward," Boehner said shortly after the chamber began debate.

"No just society should condone the destruction of human life, even in the name of medical research," Boehner said.

Rep. Diana DeGette, D-Colo., criticized the president's decision. She said the president had "snuffed out the candle of hope" for Americans suffering from a number of diseases who could benefit from the research.

Bush spoke in the East Room after vetoing the measure, saying he did so to uphold values on human life.

"In this new era, our challenge is to harness the power of science to ease human suffering without sanctioning the practices that violate the dignity of human life," Bush said in the East Room of the White House after vetoing the measure.

Bush announced his veto surrounded by 18 families who "adopted" frozen embryos not used by other couples to have children, otherwise known as "snowflake babies."

"Each of these children was still adopted while still an embryo and has been blessed with a chance to grow, to grow up in a loving family. These boys and girls are not spare parts," Bush said after several interruptions of applause from supporters. "They remind us of what is lost when embryos are destroyed in the name of research. The remind us that we all begin our lives as a small collection of cells. And they remind us that in our zeal for new treatments and cures, America must never abandon our fundamental morals."

Rep. Roscoe Bartlett, R-Md., released a statement in support of the veto, saying it is possible to study "pluripotent" stem cells, believed to be equally useful but not derived by destroying embryos. He sponsored a bill proposing such a plan, but it failed a two-thirds vote in the House. The Senate unanimously passed an identical bill.

"I'm hopeful that the House members who voted against my bill before the president's veto will decide they want to take it up again and approve it," Bartlett said.

With the Senate's passage of the legislation Tuesday, the bill was put on a virtual collision course with the president's desk. In August 2001, Bush permitted existing federal research to continue, but has fervently advocated against increased government funding. He and others argue that stem cells that come from human embryos — unlike stem cells derived from adults — can only be harvested through the loss of a human life.

"The president believes strongly that for the purpose of research, it's inappropriate for the federal government to finance something that many people consider murder. He's one of them," said White House spokesman Tony Snow.

Bush argued that the bill would have crossed a line and "once crossed, we would find it impossible to turn back."

At the same time, Bush announced he had signed another bill, passed unanimously in the House and Senate, that would pre-emptively ban "fetal farming," the prospect of raising and aborting fetuses for scientific research.

The veto came a day after the Senate defied Bush and approved the legislation, 63-37, four votes short of the two-thirds margin needed to override. Stem cells are considered by a number of scientists to be a possible key to unlocking the secrets of, and developing cures for, many difficult diseases and medical problems such as Alzheimer's, paralysis and other brain-function disorders. The House passed the original bill in May 2005.

Many scientists say the embryonic stem cells hold more hope than their adult-derived counterparts because they are the cells that multiply into the many types of cells that build the human body. Adult stem cells do not act the same way.

"Those lives will not begin, but many other lives will end if we do not use all the scientific resources available," said Sen. Arlen Specter, R-Pa., referring to the multitude of discarded embryos sitting in fertility clinics that could be plied for the favored embryonic stem cells.

Several high-ranking and conservative celebrities — including former first lady Nancy Reagan, whose husband, President Ronald Reagan, suffered from Alzheimer's — have said they believe that embryonic stem cell science could eventually save millions of lives.

The Senate vote was preceded by two days of debate, which also involved a number of personal stories to highlight the possible impacts of the research.

The House and Senate votes reflected public opinion polls. A May Gallup poll showed that 61 percent of respondents found research of human embryo stem cells morally acceptable. The same poll, however, showed that only 43 percent believed abortion was morally acceptable.

Proponents said the bill lifting that restriction also puts strong ethical guidelines in place, requiring donors to give their informed consent for using embryos that would otherwise be discarded.

"The unfortunate part is, if the president does veto the bill, then it sets us back a year or so until we can finally pass a bill that will have the requisite supermajority to be able to become law," said Sen. Orrin Hatch, R-Utah. "And that sets back embryonic stem cell research another year or so."

Senate Majority Leader Bill Frist, R-Tenn., a surgeon who pushed for expanding federal funding for embryonic stem cell research, said Bush in private conversation vowed not to let any more embryos be destroyed for research with federal money on his watch.

Democrats said two other stem cell bills under debate Tuesday were designed to appease voters angry that the GOP-led government had not opened more doors to research.

"Their opposition to stem cell research is outside the American mainstream, so they want to give themselves political cover by voting for two meaningless bills," said Senate Minority Leader Harry Reid. "It's a playbook straight from the Republican Orwellian world of politics."

The Associated Press contributed to this report.