Scientists genetically modify human embryos in controversial world first

New procedure used to modify disease-causing gene, but raises questions over whether restrictions should be placed on new wave of genetic techniques

Scientists in China have genetically modified human embryos in a world first that has re-ignited the debate over the ethics and safety of genetic therapies that have the potential to prevent inherited diseases.

The work raises fresh questions over whether restrictions should be placed on a new wave of genetic techniques that are rapidly gaining ground in labs across the world.