Maverick scientists attempting to clone humans should be outlawed across the world, a leading expert has said.
Human cloning is condemned by many experts
Lord Robert May, president of the Royal Society, said "cowboy cloners" caused great public anxiety and should be stopped.
He joined a group of leading scientists to make an appeal to the media to stop reporting human cloning claims.
Last week, US fertility expert Dr Panos Zavos claimed he had transferred a cloned embryo into a woman's womb.
Dr Zavos said there was a 30% chance of the woman becoming pregnant, but he refused to reveal any details of the woman or where the procedure took place, saying only that it was not in the US, the UK or the rest of Europe.
It was the latest in a line of claims by a number of scientists carrying out reproductive cloning research.
Lord May said: "What is real is the public anxiety that such claims cause - particularly when accompanied by a flurry of publicity.
"It is important, therefore, that every country introduces effective legislation to deter cowboy cloners."
Writing in Global Agenda, the magazine of the World
Economic Forum's annual meeting, which starts on Wednesday in Davos, Switzerland, Lord May said research had shown that cloning primates was technically much more difficult than with other animals.
He wrote: "Few disagree that it would be extremely irresponsible to try such an unsafe technology on people."
Lord May said advocates of the reproductive cloning of people "seem more motivated by the publicity of carrying out such experiments... than by a genuine regard for the plight of the human guinea pigs that would take part."
He said many countries had not banned the practice because they linked it with therapeutic cloning - backed by many scientists who believe it could lead to the development of new stem cell treatments.
Lord May said a clear distinction had to be made between a technology and its potential applications, whether "good" or "bad".
He added people had to be reassured that scientific knowledge was not being misused.
The Royal Society also called on cloning researchers to answer a number of key questions about their work including:-
- Have potential health risks for the woman and child been considered?
- What suggests human cloning would be successful?
- Will the research be open to independent scrutiny?
Lord May, along with a dozen other experts, signed an open letter calling on the media not to publicise unsubstantiated claims that a scientist had cloned a human.
They wrote: "We fear that the disproportionate coverage given to these stories conveys the impression that fertility scientists in general are engaged in the race to clone the first human being.
"In fact the opposite is the case.
"Mainstream fertility experts are united in their opposition to this work and parliament has banned reproductive cloning in the UK."