Diseases past down the generations could be wiped out with a breakthrough IVF gene swap.
Scientists created healthy infant monkeys by switching defective genes in the mitochondria - cell "power plants" - in the mothers' eggs.
If the treatment is approved for humans it could put an end to illnesses caused by such genes. These include crippling nerve illnesses similar to multiple sclerosis.
Mitochondrial DNA is also believed to play a role in Alzheimer's, Parkinson's and Huntington's as well as cancers and diabetes.
Dr Shoukhrat Mitalipov, one of the US team that made the breakthrough at the Oregon National Primate Research Center, told the journal Nature it could "rapidly be translated into clinical trials for humans".