A controversial US fertility specialist who says he has implanted a cloned embryo into a woman's womb has been condemned as "irresponsible" by scientists.
Dr Panos Zavos has provided no evidence to back up his claims
Dr Panos Zavos gave few details and no evidence, and said it was still too early to tell if the procedure had resulted in pregnancy.
But UK Health Secretary John Reid condemned the attempt to create a cloned human baby as a "gross misuse of genetic science".
Fertility experts said if true, it was an "incredibly risky" step to take, and said Dr Zavos was giving false hope to people desperate to have children.
Dr Zavos made his announcement at a news conference in a central London hotel on Saturday.
He said the embryo came from the immature egg of the infertile 35-year-old woman, and a skin cell from her husband.
He said it was a "very recent event" that did not happen in the US, the UK or anywhere else in Europe.
They were still waiting to see if the implantation had been successful, of which he said there was a 30% chance.
"I do not have a pregnancy to announce - stand by two or three weeks when we will know more," he told reporters.
The doctor also claimed the procedure had been filmed, and he would allow DNA testing to check his claims at a later date.
Reproductive cloning takes DNA from the donor and transfers it into an egg which has had its nucleus, and therefore most of its own genetic material, removed.
It is similar to the technology used to create Dolly the sheep, but its use on humans is illegal in the UK.
Dr Zavos says his work gives hope to infertile couples by offering them the chance of a different sort of baby.
But critics say that aside from ethical considerations, human cloning is incredibly risky and animal experiments in the field have often led to premature deaths and abnormalities.
Professor Richard Gardner, chairman of the Royal Society's working group on cloning, said: "To embark on human cloning at this stage with our current knowledge of what
happens in animals, just seems to me quite astoundingly irresponsible."
Bob Ward, from the UK National Academy of Scientists, called the news conference a "circus" and told BBC News: "Like most scientists and doctors I remain extremely sceptical of the claims made here today."
He said there was nothing to distinguish the announcement from the Raelian cult's claim in 2002 that it had produced five cloned babies, for which no proof had ever been produced.
Dr Zavos also announced he was "ready" to split a human embryo into two.
One could be grown into a baby, and the other could become a second baby or, "futuristically", stored and used as a source of stem cells to treat the first baby should it become ill.
Peter Braude, fertility expert at King's College Hospital, said: "The idea of splitting embryos is not new - it was done in animals 15 years ago.
"But it has always been accompanied by low success rates and has therefore never been accepted for us in humans."