A maverick US-based fertility expert said yesterday that he had transferred a cloned human embryo into a woman, but leading scientists immediately expressed scepticism, saying it was highly unlikely.
Dr Panos Zavos told a stunned news conference in London the embryo had been transplanted at an undisclosed location less than two weeks ago and that he was still waiting to see if it had implanted successfully.
"We transferred the first cloned embryo into a 35-year-old woman. Since it has not been two weeks since we transferred the embryo, we are waiting for the results of the pregnancy," he said.
Zavos travelled from the US to Britain, where human reproductive cloning is banned, to make the announcement.
British Health Secretary John Reid denounced the claim which drew criticism from many quarters, including the Vatican.
Scientists doubted that Zavos had cloned a human embryo and challenged him to produce scientific evidence and to publish his results in a scientific journal so they could be reviewed by experts.
"It is highly unlikely that he has successfully made a cloned human embryo," said Chris Higgins of Britain's Medical Research Council (MRC). "So far he has produced no data at all."
Peter Braude, a fertility expert at King's College London, said: "Zavos does not represent mainstream science and what he and his colleagues are doing is seeking publicity rather than advan-cing science."
The European Society of Human Reproduction and Embryology (ESHRE), which represents 4,000 fertility experts around the world, condemned the cloning claim.
"It is totally irresponsible and unethical to attempt human reproductive cloning. Apart from the ethical objections, which are serious enough, there are major practical problems, not least of which is the high chance of abnormal babies -- even if those abnormalities are not apparent at birth," said ESHRE chairman Arne Sunde.
Research on animals has shown that cloned embryos often do not survive to produce a live birth. Sometimes they die shortly after birth or they can develop serious health problems later in life.
Zavos has been saying since May 2002 that he was ready to try to create a human clone. Last October he said he was only weeks away from implanting a cloned embryo in a surrogate mother but leading fertility experts dismissed the claim.
His former colleague, Italian fertility doctor Severino Antinori, said nearly two years ago that three women were pregnant with clones. He produced no evidence.
The Raelian Movement, a cult that believes life on Earth was engineered by visitors from outer space, a year ago said it had produced the world's first cloned human but it never produced any scientific proof.
Zavos said the embryo he had transferred was from an unidentified woman who was entering premature menopause. He says the egg was harvested from her body and fertilized with DNA taken from skin cells donated by her infertile husband.
Zavos said he was optimistic but admitted that the chances of the woman's pregnancy going to term were slim.
He said he would continue until he had success and added he was looking for more volunteers.
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