Human embryo research touches upon strongly felt moral convictions, and it raises such deep questions about the promise and perils of scientific progress that debate over its development has become a moral and political imperative. From in vitro fertilization to embryonic stem cell research, cloning, and gene editing, Americans have repeatedly struggled with how to define the moral status of the human embryo, whether to limit its experimental uses, and how to contend with sharply divided public moral perspectives on governing science.

Experiments in Democracy presents a history of...