A scientist in New York is conducting experiments designed to modify DNA in human embryos as a step toward someday preventing inherited diseases, NPR has learned. For now, the work is confined to a laboratory. But the research, if successful, would mark another step toward turning CRISPR, a powerful form of gene editing, into a tool for medical treatment. A Chinese scientist sparked international outrage in November when he announced that he had used the same technique to create the world's first gene-edited human babies. He said his goal was to protect them from infection with HIV, a claim that...