This will hopefully give Nathan the sort of life he deserves

Denise Kelly

However, he has no brothers or sisters who could provide a match - and a search of international registers has drawn a blank.

She wants have IVF treatment - but with the embryos screened both for the gene which causes the illness - and to make sure the new baby was a tissue match for Nathan.

She is prepared to go to America, where this is offered, but would need to find tens of thousands of dollars to pay for it.

Denise is prepared to go to the US

However, the HFEA ruling has opened the possibility that UK clinics could offer the service.

She said: "Nathan is my world, and he is his father's world, and we will do everything we can to keep that world together.

"I think the UK needs to get up with the technology - all the other countries are going to be doing it, so why should the UK be any different?"

No favouritism

She said that while she disagreed with the idea of "designer babies" when it came to choosing the sex, or even the eye colour of children, her circumstances were different.

"When it's a medical issue, and it could save another child's life, it should be looked at."

When it's a medical issue, and it could save another child's life, it should be looked at

Denise Kelly

She said that she had wanted another child, but the chance of having another one with the same illness - reckoned to be one in four - had deterred her.

But she denied that the only reason she wanted one now was to provide bone marrow for Nathan.

"We will love that child no matter what," she said.

Fast action

Now the HFEA decision has arrived, she wants to move quickly.

"The first thing I'm doing is getting on the phone to the specialist and starting treatment straightaway.

"This will hopefully give Nathan the sort of life he deserves."

However, the HFEA has said that, at the moment, the ruling does not represent a go-ahead for every couple who wants to follow in the Hashmi's footsteps.

At the moment, every case will be considered on its own merits, and both Denise and Nathan face an anxious wait to find out if their case is successful.