Given how controversial genetically modified corn is, it's no wonder that the prospect of genetically modifying humans pushes a lot of people's buttons. But we already have gene therapies, and new technologies are making it faster, safer, and less expensive to modify the human genome in a range of ways. That has the science community and policymakers scrambling to set responsible guidelines for the use of genome editing. In 2015, the International Summit on Human Gene Editing recommended holding