In April, a group of scientists reported in the online journal Protein & Cell that they had edited human embryos using a gene editing technique called CRISPR. How should research progress as human gene editing techniques become cheaper, faster, and more precise? George Q. Daley, Director of the Stem Cell Transplantation Program at Boston Children’s Hospital and Dana Farber Cancer Institute, and Alta Charo, a Professor of Law and Bioethics at the University of Wisconsin, discuss the promises and perils of engineering the human genome.