The children born with a gift of life for their siblings

Charlie and Jamie Whitaker will always have a special bond. Not just because they are brothers, but because Jamie's birth saved his big brother's life.

"Jamie is very proud of the fact that he helped his brother," says his mum, Michelle. "Some said at the time that he would be messed up because he would think he was a spare parts child. Nothing could be further from the truth. We love all our children the same, in fact, Jamie is really proud of the fact that he was able to help Charlie. It is all about parenting and how you talk to your children."

Charlie, now a healthy 11-year- old, was born with a very rare blood disease, Diamond Blackfan anaemia, which stopped him producing enough red cells. His only chance was a bone marrow transplant from a sibling with the same tissue type.

Jamie was the first so-called "saviour sibling" to be born in the UK, at Sheffield's Jessop wing, at the Hallamshire Hospital, although his parents had to travel to America for treatment after they were denied the procedure in this country which would ensure he was a perfect tissue match for Charlie.

The controversial screening process known as pre-implantation genetic diagnosis (PGD) was banned in Britain until Leeds couple Raj and Shahana Hashmi won a High Court ruling in 2005 to allow them to have PGD to try for a saviour sibling for their son Zain, who was suffering the rare blood disorder, beta thalassaemia

The procedure, using IVF, involves screening embryos in the laboratory to ensure they are a perfect tissue match and, in some cases, free from disease, before they are reimplanted in the mother.

Now two other Yorkshire couples are going through the process in a bid to save their children from a condition called Fanconi anaemia, a degenerative disease which attacks the bone marrow and the red blood cells.

David and Samantha McDowell, from York, lost their daughter Jess, 11, to the disease two years ago after her body rejected a bone marrow transplant from her dad.

The family now face the same tragedy with two-year-old Alex unless a bone marrow match can be found, but so far the search has proved fruitless.

They have just won a year-long battle for 7,000 NHS funding for one cycle of IVF and PGD which they hope will produce a healthy child free from Fanconi anaemia which will save Alex's life. If successful, the child will be the first "saviour sibling" paid for by the NHS.

David, who has set up the charity Fanconi Anaemia Family Support, says: "We're not talking about 'I want a baby with blonde hair and blue eyes', that's not what we are talking about.

"We're talking about a child who is healthy."

The McDowells' fight has been filmed by a documentary crew and will be screened on BBC1 on Tuesday.

Having a Baby to Save a Child also follows Sheffield couple Alison and Tom as they go through the process of trying for a baby to save their four-year-old son, David. As practising Catholics, the idea of using IVF techniques to "create" a child to cure another one has created a moral dilemma.

Alison says: "We're trying to choose a baby that's not only a baby for us but a baby that will help David. I guess ethically there are a lot of strong opinions about whether we should or shouldn't be having a go at doing this."

Critics say PGD is a slippery slope to designer children, but Mrs Whitaker disagrees strongly.

"We did not know the sex of our baby or the colour of his hair. All we knew was that he had the same tissue as Charlie and could save his life."

"Charlie had to undergo blood transfusions every two weeks. We had to inject him with steroids and he would be in tears begging us not to hurt him.

"It was heart-breaking but we had to do it or he would have died," says Michelle.

"We were always honest with him. He knew he had to have Billy Blood as he called it and his Jungle Juice to keep him alive."

His only hope of survival was a transplant using stem cells from a sibling's umbilical cord.

"We had always wanted a large family, but there is no way of screening for Diamond Blackfan anaemia. When I fell pregnant

with my second child Emily (now eight), they said there was a 1:50 chance she would have it."

When Emily was born, Michelle and husband Jayson fought to have her umbilical cord preserved in case she was a match for Charlie, but it turned out not to be. "We were so relieved that she didn't have Diamond Blackfan anaemia, we weren't disappointed she wasn't a match."

They then heard about the Hashmi case and asked their consultant to look into PGD, but they were devastated when the Human Fertilisation and Embryology Authority (HFEA) refused their request.

But they flew to Chicago for the procedure which, in 2002, saw two three-day-old embryos implanted in Mrs Whitaker and, in June 2003, she gave birth to Jamie. Stem cells from the umbilical cord were harvested and 12 months later they were transplanted into Charlie.

"That was the hardest part," recalls Mrs Whitaker, who lives near Bolsover, Chesterfield.

"Charlie was so well that it made the decision to go ahead with the transplant really difficult. It wasn't a decision we took lightly and there was a time when I thought that we might have made the wrong decision, but looking at him now, it was worth it all."

Nearly six years on, Charlie has been given the all-clear from Sheffield Children's Hospital, though he still has annual check-ups. His bone marrow

is working properly and he is clear of Diamond Blackfan anaemia.

"People have IVF all the time and select embryos to implant. All we have done is select an embryo that is a tissue match to Charlie. Jamie is loved for being Jamie. It just happens that he was also able to help his brother," says Michelle.

Adel Shaker, of the CARE fertility clinic in Sheffield, who treated the Hashmis, says that every case has to be taken on its own merits.

"To be able to have a child to save another child has to be a positive thing, but we have to ensure the welfare of that unborn child.

"So far all the experiences of saviour siblings have been positive with all the necessary checks and balances in place.

"People should take heart from that if they are considering this procedure, although every case should be taken on its own merits and should win ethical approval from the HFEA."

For more information on Fanconi anaemia visit www.fanconi.org.uk

Having a Baby to Save My Child is on BBC1 on Tuesday, February 16, at 10.35pm.