A maverick US-based fertility expert said today he had implanted a cloned human embryo into a 35-year-old woman and was looking for more volunteers.
Launching an international search in London for women willing to be the surrogate mothers of cloned human embryos, Dr Panos Zavos said he was still waiting to see if the implantation had been successful.
"We transferred the first cloned embyro 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 told a stunned news conference.
His shock announcement drew scepticism in some quarters.
"This is not the first time Doctor Zavos has made claims without producing any form of evidence to substantiate them," Mr Patrick Cusworth of anti-abortion charity LIFE told reporters.
"LIFE as an organisation would probably greet Doctor Zavos' latest claim with a certain amount of scepticism," he added.
Dr Zavos said the embryo he had implanted in the unidentified woman, who was entering premature menopause, had grown from an egg which was harvested from her own body and fertilised with DNA taken from skin cells donated by her infertile husband.
He said the skin cells were transformed into a "species" of cells that were fused with the egg.
"After that happened the fusion took place. The activation took place. The embryo took off and developed properly. It was a very healthy-looking embryo. We decided with the consent of the patient to transfer that embyro, and we did," he explained.
"We are very optimistic that the results will be positive," he added.