United Nations ? In a setback for Washington, the United Nations narrowly blocked moves by the United States and other countries Thursday to approve a global ban on human cloning because the proposal also would have constrained stem cell research.

The General Assembly’s legal committee, which includes representatives of most U.N. members, voted 80-79 to delay consideration of a treaty to ban human cloning for two years. Fifteen members abstained and some missed the vote.

Even if the resolution had been adopted, the ban would not have been legally binding, leaving each country to decide whether to enforce a worldwide convention. But U.S. deputy ambassador James B. Cunningham said it would have been “an important political signal and statement of principle that should help set an international standard.”

While all of the 191 members agreed that human cloning should be prohibited, they were sharply divided on whether also to halt related medical research. The United States backed a Costa Rican proposal that would constrain stem cell research, which scientists say shows great promise in curing diabetes, Parkinson’s disease, leukemia and spinal cord injury.

In an unusually passionate debate that involved religious, ethical and human rights issues, the United States argued that extracting stem cells involves the destruction of an early-stage embryo — and thus human life.

Others said a cluster of 150 cells in a petri dish did not represent a potential human being, and that the research had overwhelming benefits for living people.