The UN General Assembly's legal committee begins a two-day debate today on human cloning.
There is almost universal support among the 191 UN member states for a global treaty banning human cloning, but deep divisions exist over the use of human embryos for medical research.
The debate will focus on rival resolutions: Costa Rica's draft calls for a treaty that would ban all cloning, while Belgium's draft calls for a treaty that would ban the cloning of babies, but allow countries to decide on using embryos for research, which many scientists believe may lead to new treatments for a range of diseases.
Last November, the legal committee voted by 80-79 to delay consideration of a cloning treaty for two years, a move requested by Islamic nations. But in December, the General Assembly decided without a vote to delay the discussion of a global treaty for just one year.
South Korean scientists announced in February they had cloned an embryo and extracted the stem cells from it. Britain granted its first licence for human cloning for stem cell research in August.
Both countries are among the 22 co-sponsors of the Belgian resolution that would authorise a committee to draft a convention banning reproductive cloning of human beings without "any reservations".
It would also require all countries that adopted the treaty to ensure that the results of "therapeutic cloning" - the use of human embryos for medical research - are not used to advance human cloning.
AP