London ? The international community faces a stark choice: outlaw human cloning or prepare for the creation of cloned humans, U.N. researchers said Saturday.

Previous attempts to reach a worldwide treaty foundered over divisions on whether to outlaw all cloning or permit cloning of cells for research.

The best solution may be to ban human cloning, but to allow countries to conduct strictly controlled therapeutic research, including stem cell research, according to the report from the Japan-based United Nations University Institute for Advanced Studies.

Almost all countries oppose human cloning and more than 50 nations have introduced laws banning it. But lack of binding global legislation gives scientists an opening to create human clones in countries where bans do not exist.