An influential think tank on ethics has given the all clear to a new technique for preventing genetic diseases that affect 6,000 people in the UK.
The technique has been controversial because it involves creating embryos by IVF that have genes from three "parents". But the Nuffield Council on Bioethics says the genetic contribution from the "third parent" is so small, essentially it can be ignored when considering ethical issues.
Around a hundred babies a year are born with genetic defects in what scientists call mitochondrial genes. Children like Adam who is now 11. And he's beginning to suffer because of mutated mitochondrial genes he inherited from his mother Marie.
Mitochondria are the "batteries" contained in every cell in your body. What's unusual is that they contain genes - but only about 13 of them, 0.1 per cent of the genes you inherit. When they go wrong, the mitochondria in every cell, whether its your kidneys or your heart or your muscles, dont work properly.
Adam uses a wheelchair because he gets so exhausted he needs it to get him through the day. He's already been assessed for a kidney tramsplant and will probably need a heart transplant at some stage. He already takes eight or nine medications a day.
He inherited those "bad" mitochondrial genes from his mother - fathers dont pass on their mitochondrial genes to their children.
But now scientists in Newcastle have worked out a way of prevening these devastated diseases.
They would take an egg from a mother to be and remove the nucleus, which contains 99.9 per cent of her genes including all the ones that make us what we are. They'd then insert that nucleus into a donor egg whose mitochondrial genes were OK and fertilise the eggs with the father's sperm and use IVF to implant the embryo. The bad genes dont get passed on.
Trouble is, critics say the enbryo would be a "genetic" hybrid with three parents. The Nuffield report knocks this idea very firmly on the head. The "third parent" would contribute a tiny part of the embryo's genetic inheritance - children born this way wouldn't even need to know who the donor was, they say.
Its a big boost for the technique, but not the end of the road yet. For a start the scientists in Newcastle are still testing it in the lab to show that its safe and can effectively produce embryos.
Then the government regulator, the HFEA has to approve the technique and then there would have to be a parliamentary vote to change the law because this kind of technique is currently illegal.
So it may well be several years before doctors can use the new technique. Too late for Marie, but probably in time to help her daughter, who's seven and is a "carrier", to have healthy children.