IT is a decision which could bring hope to many families.

The vote by MPs to legalise mitochondrial donation, the controversial technique allowing the creation of IVF babies with DNA from three different people, could mean Britain becomes the first country in the world to permit the procedures which are aimed at preventing serious inherited mitochondrial diseases.

For the families that could benefit, the move could be the breakthrough they need. Mitochondrial donation could potentially help more than 2,400 women in the UK, according to new research, and if the House of Lords approves the decision - which seems likely - the first baby conceived with the treatment may be born as early as next year.

All the women are said to be at risk of transmitting harmful DNA mutations in the mitochondria, tiny rod-like power plants in cells, onto their children and future generations.

The new treatments would allow a child to receive normal "nuclear" DNA from its mother and father, but also a small amount of healthy mitochondrial DNA (mDNA) from a woman donor.

Liz Curtis, who along with her family set up the The Lily Foundation in October 2007, following the death of her eight-month-old daughter Lily from mitochondrial disease, says: "Obviously we still have to get it through the House of Lords but I think overall the consensus is we are really chuffed it made it through the Houses of Parliament and will give families a little bit of light at the end of a long dark tunnel."

Now other families affected by genetic conditions are hoping the exploration of such science may help eradicate the conditions and diseases affecting their lives for future generations.

Melanie King's son, Steven - now 25, was six when he was diagnosed with Duchenne Muscular Dystrophy, a genetic condition where slow, progressive muscle wasting leads to increasing weakness and disability.

The mum-of-three from Bradford welcomes the move saying it may help other families. "I do think it will be a good thing," says Melanie.

Cystic Fibrosis sufferer, 31-year-old Sharee McPhail also from Bradford, says: "I don't think the technology would help yet from what I have been reading. I think the science is a little bit more complicated, but from what I have read they hope the technology in the future may be able to help to eradicate CF as well."

Dr Janet Allen, Director of Research & Care for the Cystic Fibrosis Trust says: “This is a hugely important debate which shows that the UK is leading the way in developing and implementing novel approaches that can help people who carry genetic conditions such as cystic fibrosis.

“The formation of the Human Fertilisation and Embryology Authority continues to provide an excellent framework for this debate and ensures new approaches to treatments are introduced in a safe and considered fashion.”

Cathy Ranson, editor in chief of the UK’s biggest parenting site Netmums said: “Changing the course of nature is always seen as controversial, but labelling babies born from the treatment as ‘designer’ is missing the point. No parents wants to have to go through this procedure - but when it’s your only hope of having a healthy child with a chance of life, it’s understandable you may want to try it."

Among the supporters of the amendment are IVF pioneer and broadcaster, Lord Winston, who argued that it would be immoral not to take advantage of a technique that could prevent devastating and potentially lethal diseases. They pointed out that even though no medical technique has zero risk, three in-depth reviews by experts have concluded that mitochondrial donation is "not unsafe."

They also stressed that even with the change to the law, it does not follow that women will automatically be treated. It will be up to the fertility regulator, the Human Fertilisation and Embryology Authority (HFEA) to judge each application on its merits and decide whether or not it should be approved. Licences permitting mitochondrial donation will only be granted if the Authority is satisfied that women or their babies will be not in danger.

Mitochondrial DNA only accounts for 0.1 per cent of a person's total DNA and affects metabolism but not individual characteristics such as facial features and eye colour which are determined by nuclear DNA. Changing the law to allow mitochondrial donation in no way affects the firm ban on altering nuclear DNA or reproductive human cloning, it is claimed.

But critics such as the Human Genetics Alert and the Roman Catholic Church in England and Wales, maintained that despite the scientific reviews, the decision to legalise mitochondrial donation has been taken too hastily.