Scientists from around the world have called for an international ban on the cloning of humans to make babies.
It may not be possible to clone a baby
Only a few countries, including the UK, have so far outlawed it.
All attempts to introduce a world-wide ban have been stymied because some countries want that to include the use of all cloning techniques in medical research.
However, many researchers believe the use of some cloning technology could lead to a revolution in medicine.
The Inter-Academy Panel, a network of scientific societies representing the world's leading researchers, has called for a specific ban on what they term reproductive cloning.
It is not opposed to the use of cloning techniques to find treatments for incurable diseases.
The move has been backed by Lord May, the president of the Royal Society, the UK's academy of science, who said human reproductive cloning must be banned to prevent unscrupulous people from exploiting the vulnerable.
Lord May said that such human cloning was a threat to the health of both the cloned child and the mother.
He called attempts to clone babies "grossly irresponsible".
"It would be a tragedy if we allowed disagreements on therapeutic cloning to jeopardise a convention that could ensure that human reproductive cloning is outlawed across the globe and protect vulnerable people from unscrupulous individuals," he said.
The United Nations is to debate human cloning next week.
Theoretically, it should be possible to clone a human by removing the DNA from the nucleus of an egg cell taken from a woman.
This DNA would then be replaced by the genetic material taken from a cell from the person who is to be cloned.
A trigger would be applied to the egg cell that would then make it start to divide like any normal embryo.
The woman would have it implanted in her womb in a procedure which is routinely performed in IVF clinics.
However, US research published earlier this year suggests that it may never be possible successfully to clone a human because of the specific biological make-up of the eggs of primates, including humans.
Although animal experiments have produced successful clones, the vast majority of pregnancies have gone badly wrong.
There are also concerns about the health of cloned animals once they are born.
An organisation called Clonaid, which is linked to a sect that believes aliens created humans by cloning 25,000 years ago, has claimed to have cloned five human babies since last December.
But many scientists have dismissed the claim, pointing to the company's failure to provide DNA proof.