A boy has been born to a British couple who want to use stem cells from his umbilical cord to treat an older brother with a life threatening blood disorder.
Jamie and his brother, Charlie
Michelle and Jayson Whitaker's baby, Jamie, was genetically selected while he was still an embryo to be a near perfect match to four-year-old Charlie.
The couple went to an American clinic for test tube baby treatment because the selection procedure is not allowed in the UK.
It is not the first UK baby selected to help cure a sibling - a couple whose child was suffering from leukaemia and needed a bone marrow transplant took the same route in 2001.
Other babies "designed" to help their siblings have been born in the US.
The UK doctor treating the Whitakers, Mohammed Taranissi, says he is aware of dozens of other couples who want to undergo the same procedure.
"I just hope this will bring hope to everybody else in the same situation.
"Maybe in a year or two down the line we will be looking at a standard procedure rather than something that we have challenge and go to court to try to make it happen," he told the BBC.
Jamie was born by Caesarean section at the Jessop Wing of Sheffield's Royal Hallamshire Hospital on Monday and his arrival will re-ignite the debate about so-called designer babies.
Dr Lana Rechitsky from the Reproductive Genetics Institute in Chicago, who matched the Whitaker tissues, told the BBC Jamie was the second baby born in Britain as a tissue match.
But the condition of the sibling of the first child has gone into remission and treatment had not been necessary so far.
Jamie's brother suffers from a rare and potentially fatal form of anaemia, which requires a regular, painful treatment.
It can only be cured by a transplant of
stem cells from a sibling with a perfect tissue match.
Mr Whitaker, a 33-year-old business manager who recently moved to Derbyshire from Bicester in Oxfordshire, said that he and his wife had made the right decision.
He told the Daily Mail newspaper: "All we did was
change the odds from a one-in-four chance of a tissue match to a 98% chance.
"There was no selection on the basis of colour of eyes or hair or sex."
Mr Whitaker added: "There are blood tests being carried out now to see if Jamie is a perfect tissue match and we will know in a few days, but at the moment we don't want to think about the stem cell blood."
The stem cells have already been collected from Jamie's umbilical cord and tests will also be carried out to see whether he has the same condition as his brother.
Dr Rechitsky said the technique had worked previously for a family in the US.
"We performed exactly the same IVF procedure and we found matched embryo and we transferred these embryo and the famous Adam Nash was born," she said.
"His stem cells from his umbilical cord were used for his sister Molly and Molly right now is completely cured."
The Whitakers applied for permission in 2002 to allow IVF doctors in the UK to select an embryo that provided a perfect match for Charlie.
However, regulators refused permission on technical grounds.
The Human Fertilisation and Embryology Authority said it was acceptable to test and select embryos to prevent the birth of a baby with a genetic disease, but not to select them in order to help another child.
The Whitakers travelled to the US
But John Smeaton, national director of the Society for the Protection of Unborn Children, said: "While our hearts go out to everybody involved, and we welcome Jamie Whitaker's birth, there are profound issues of concern here.
"Human beings who were not the perfect match were simply discarded and a child has been created with the primary purpose of benefiting his elder brother. This does not conform to Jamie's human dignity.
Since the Whitakers flew to the US for treatment, another British couple have won the right to have a "designer baby".
Raj and Shahana Hashmi hope their child will provide a donor for their sick son, four-year-old Zain.
The couple, who live in Leeds, won a Court of Appeal case which gave them the go-ahead to allow doctors to screen embryos to find a perfect match.
The family will know by the end of June whether the IVF treatment has been successful.
The difference between the Hashmis' case and that of the Whitakers is that Zain's condition is hereditary so the couple can screen future embryos to check that they do not have the disease - and at the same time find out if there is a tissue match.