By an overwhelming margin, the House voted yesterday to outlaw all forms of human cloning.

The legislation, which passed 241 to 155, would prohibit the production of cloned human embryos for medical research as well as the creation of cloned babies. It parallels a 2001 vote in which a significant number of Democrats joined Republicans in voting to make cloning a federal crime.

The measure faces an uncertain future in the Senate, which is closely divided on the question of whether embryo cloning should be prohibited along with baby cloning. Senate Democrats blocked the House bill from a vote in the last Congress. Now Senate Majority Leader Bill Frist (R-Tenn.), a heart surgeon who has sought middle ground on human embryo research issues, must decide how hard to push for what President Bush has identified as a significant priority.

Bush on Wednesday made his feelings clear, releasing a policy statement that "strongly supports" a total ban. "The administration is strongly opposed to any legislation that would prohibit human cloning for reproductive purposes but permit the creation of cloned embryos or development of human embryo farms for research, which would require the destruction of nascent human lives," the statement said.

Virtually every lawmaker on the Hill agrees that Congress ought to ban reproductive cloning, or the creation of cloned babies -- an act that many consider tantamount to playing God. Clones, which are genetic replicas of their parents, often harbor genetic anomalies -- at least in the handful of animal species in which clones have been made. Many experts suspect that human clones could additionally suffer psychological harm, in part because they might feel that their lives had already been lived by someone else.

But members differ over whether a cloning ban should also preclude the creation of cloned human embryos, which could serve as a source of embryonic stem cells. Stem cells can morph into all kinds of cells and tissues, and many researchers believe the cells can be modeled into replacement parts for people suffering from spinal cord injuries or degenerative diseases, including Parkinson's and diabetes.

Proponents believe that stem cells derived from cloned human embryos may have medical advantages over those derived from conventional embryos or from adults. A measure sponsored by Reps. James C. Greenwood (R-Pa.) and Peter Deutsch (D-Fla.) that would have allowed embryo cloning but precluded reproductive cloning failed 231 to 174.

Throughout the afternoon, lawmakers sparred over how best to police the frontier of biomedical research, with supporters of the total ban suggesting that Congress needs to send a clear message that cloning experimentation will not be tolerated.

"This is a moral and ethical decision," said Rep. David Joseph Weldon (R-Fla.), a practicing physician who was author of the cloning ban along with Rep. Bart Stupak (D-Mich.). "We're talking about creating human embryos for the purpose of experimenting on them and destroying them. There's no evidence today that is justifiable."

Opponents countered that the bill's sponsors were placing ideology before the practical goal of easing Americans' suffering, and were making a tragic mistake by blocking a possible avenue of medical innovation.

"This is a turning point in our history," Greenwood said. "This is a question of whether you go forward with the most promising medicine of our time."

By imposing a maximum penalty of $1 million in civil fines and as many as 10 years in jail, the House bill is similar to a Senate bill sponsored by Sen. Sam Brownback (R-Kan.). But it goes further than the Senate version by prohibiting the importation of medical therapies created from cloned human embryos. Brownback's bill simply bans the import of cloned embryos.