An international group of scientists is calling for a world ban on human reproductive cloning, saying it poses a health threat to both the cloned child and the mother.
Experience of cloned animals has shown that, in the rare cases when the foetus progresses to term, it is frequently oversized - posing a risk to the mother during birth - and post-natal death is common.
The Royal Society, Britain's leading academic institution, backed the call by more than 60 other national science academies, including those of the US, China and France, ahead of a UN debate on 29 September.
Lord May of Oxford, president of the Royal Society, said: "Recent reports about attempts by unscrupulous scientists to clone humans have concerned the scientific community worldwide. Research indicates human cloning is a threat to the health of the cloned child and the mother.
"Animal studies on reproductive cloning show a high incidence of foetal disorders and spontaneous abortions, and of malformation and death among newborns. There is no reason to suppose that the outcome would be different in humans.
"Given that, attempts at human cloning seem reckless and grossly irresponsible and arguably exploitative of vulnerable people who desperately want children."
But the scientists seeking a ban on human cloning want to continue "therapeutic" cloning, in which cells from embryos are grown to provide treatments for diseases or disabilities. Anti-abortion groups oppose both forms of cloning, meaning that the UN debate on cloning next Monday will be fiercely argued.
By March last year, 33 countries had banned human reproductive cloning, but that falls far short of the worldwide ban scientists are seeking. At least three groups are trying to clone a human, including Dr Panyiotis Zavos, who announced last week that he had a cloned embryo ready for implantation in a surrogate mother before the end of the year.
He also said he was doing the work in a country where reproductive cloning was not illegal, though he would not specify which one. Countries that did not ban reproductive cloning could be sure the only people seeking it would be rich, because they were the only ones who could afford it.Reuse content