A maverick US-based fertility expert said on Saturday 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 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 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," 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.
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.