Genetic Alliance UK has welcomed the "three parent" IVF technique proposal.
The charity's director, Alastair Kent, said: "Many of these [mitochondrial] conditions are so severe that they are lethal in infancy, creating a lasting impact upon the child's family.
"An added option for families at risk of having a child with such a condition is welcome".
Experts said the technique would likely be used in around a dozen IVF cases every year.
More top news
Here is the letter sent by the broadcasters to Prime Minister David Cameron's office in relation to the planned TV leaders debates.
Machete-wielding armed robbers tied up staff and customers of a north Manchester pub during a terrifying raid.
The South African Salvation Army has used a picture of a dress that sent the web into meltdown to raise awareness about domestic violence.