Scientists in Britain have been give the go-ahead to edit the genes of human embryos for research purposes, using a technique that some say could eventually be used to create "designer babies". Less than a year after Chinese scientists caused an international furor by saying they had genetically modified human embryos, Kathy Niakan, a stem cell scientist from London's Francis Crick Institute, was granted a license to carry out similar experiments. "The Human Fertilisation and Embryology Authority (HFEA) has approved a research application from the Francis Crick Institute to use new ‘gene editing' techniques on human embryos," Niakan's lab said on Monday. It said the work carried out "will be for research purposes and will look at the first seven days of a fertilized egg's development, from a single cell to around 250 cells." The scientists will not be allowed to develop the modified embryos for clinical purposes or implant them into any women. Niakan plans to carry out her experiments using what is known as CRISPR-Cas9, a technology that is already the subject of fierce international debate because of fears that it could be used to create babies to order. CRISPR can enable scientists to find and modify or replace genetic defects. Many experts have called it "game-changing."