A US fertility specialist is planning to implant a cloned human embryo in a woman's womb but experts say it is "unethical and irresponsible".
Dr Panos Zavos says the technology will be used
Doctor Panos Zavos is to hold a press conference in London on Saturday to announce the latest details of his cloning research.
He says he is interviewing women who could act as a surrogate mother for the cloned embryo.
But critics say much more research into cloning is needed.
Reproductive cloning takes DNA from the donor and transfers it into an egg which has had its nucleus, and therefore its own genetic material, removed.
It is the same technology which was used to create Dolly the sheep.
Dr Zavos told BBC Radio 4's Today programme: "I have cloned an embryo, which is frozen at the moment.
"It is at the eight to 10 cell stage, ready to be transferred."
He defended his research, but admitted: "There is no doubt anything we do could be abused."
Several US women were being considered as a possible surrogate, he said.
Reproductive cloning is illegal in the UK, so even if a British woman volunteered to be the surrogate, she could not be treated in this country.
Dr Zavos said the chosen surrogate would have to agree to surrender the baby to the parents and also be "stable enough to do that without any emotional distress".
Critics say human cloning should not go ahead at all. They say it is unethical to clone humans, because animal experiments have led to many failures and a high rate of abnormalities in those pregnancies which do result in live births.
IVF expert Dr Simon Fischel told BBC News Online: "It doesn't matter how far advanced Professor Zavos is.
"It has to be unethical to consider reproductive cloning in humans at this point on the basis of the abnormalities that have resulted from all the animal work."
Professor Alison Murdoch, chair of the British Fertility Society, said: "We feel that giving undue credence to this unethical, dangerous and highly experimental field is irresponsible.
"The small minority of mavericks pursuing human reproductive cloning procedures are not supported by the British Fertility Society or the wider fertility community."
Dr Zavos' reaction to concern about his plans was: "People need to realise the fact that this technology is going to be made available, secure and safe and it will be applied to humans."
Dr Zavos and UK fertility specialist Dr Paul Rainsbury are also set to announce a plan to offer couples embryo splitting, where one embryo is divided into two.
One part of the embryo is implanted, and a baby is born as normal. The other is frozen and stored.
The doctors say the stored embryo could then be used as a source of stem cells throughout the baby's life.
"Families in the future will be looking for possibilities of insuring the general health status of their baby that is born by having another embryo that is similar.
"If the baby becomes ill, or develops any genetic abnormalities or deformities or injuries. then they can use that embryo to create stem cells to treat the baby's disease or deficiencies," Dr Zavos explained.
But Dr Zavos admitted they had not yet performed the technique on a human embryo
"We have split embryos in animal world with great success, but not in humans. But all intentions are that we will."