Feng Zhang, center, an institute member of Harvard and MIT's Broad Institute, reacts to reporters on the issue of world's first genetically edited babies after the Human Genome Editing Conference in Hong Kong, Tuesday, Nov. 27, 2018. He Jiankui, a Chinese researcher, claims that he helped make the world's first genetically edited babies twin girls whose DNA he said he altered with a powerful new tool capable of rewriting the very blueprint of life. If true, it would be a profound leap of science and ethics. (AP Photo/Vincent Yu)