British scientists say they have mastered a controversial technique using cloning technology to prevent some incurable inherited diseases by swapping DNA between two fertilized human eggs.
Lead researcher Doug Turnbull of Newcastle University said this week that he hoped the first babies free from so-called mitochondrial diseases would be born within three years.
The technique replaces mitochondrial DNA, which is passed down the maternal line. One in 6,500 children is born with serious diseases caused by malfunctioning mitochondrial DNA.
The technique is a variation of the one used to clone Dolly the sheep in 1996. But applying it will require a change in British law that bans reproduction from such manipulated embryos.
"A child born using this method would have correctly functioning mitochondria, but in every other respect would get all their genetic information from their father and mother," Turnbull said.