Pro and Con: Should Gene Editing Be Performed on Human Embryos?

Pro: Research on Gene Editing in Humans Must Continue

By John Harris

In February of this year, the Human Fertilization and Embryology Authority in the United Kingdom approved a request by the Francis Crick Institute in London to modify human embryos using the new gene editing technique CRISPR-Cas9. This is the second time human embryos have been employed in such research, and the first time their use has been sanctioned by a national regulatory authority. The scientists at the Institute hope to cast light on early embryo development—work which may eventually lead to safer and more successful fertility treatments.

The embryos, provided by patients undergoing in vitro fertilization, will not be allowed to develop beyond seven days. But in theory—and eventually in practice—CRISPR could be used to modify disease-causing genes in embryos brought to term, removing the faulty script from the genetic code of that person’s future descendants as well. Proponents of such “human germline editing” argue that it could potentially decrease, or even eliminate, the incidence of many serious genetic diseases, reducing human suffering worldwide. Opponents say that modifying...