Abstract

CRISPR is a powerful new biochemical tool that can be used to edit the DNA of somatic cells or the germline. It can be used for good ends such as the treatment or prevention of illness or disability, or for bad ends. All its uses for good ends can be sorted out into six kinds of cases: editing somatic cells to treat or prevent disease-a therapeutic use; editing somatic cells to enhance a living thing; editing the germline to prevent future disease-a second therapeutic use; editing the germline to enhance future living things; editing somatic cells for research to understand nature and unlock its secrets; and editing the germline for the same research purposes. Recent discussions by various experts, in the science, ethics, and governance of gene editing, show confidence in the first kind of case-that it is a good use provided the editing is safe and effective; and hesitation, doubts, and calls to stop editing in the next three cases. The paper explores the basis of our confidence in the somatic therapeutic case, and compares it systematically to the enhancement cases, while using the research cases for what they teach us about good ends. The center of this approach is that our confidence in the therapeutic somatic case is based on our agreement that health is a fundamental good, and the paper suggests an analogy between the ethics of therapy and the ethics of enhancement, which throws some light on the difficult cases of human enhancement.