Making sense of heritable human genome editing: Scientific and ethical considerations

Genome editing, particularly the use of CRISPR-Cas9-based methodologies, is revolutionizing biology through its impacts on research and the translation of these into applications in biomedicine. Somatic genome editing aimed at treating individuals with disease raises some significant ethical issues, but proposed heritable interventions, through the use of genome editing in gametes or embryos, raise a number of distinct social, ethical and political issues. This review will consider some proposed uses of heritable human genome editing (HHGE) and several of the objections to these that have been raised. Making sense of such proposed uses requires viewing HHGE as an assisted reproductive technology (ART) that, like preimplantation genetic testing (PGT) and mitochondrial replacement techniques (MRT), aims to prevent disease transmission during sexual reproduction, rather than acting as a therapy for an existing individual. Applications beyond the paradigm of disease prevention raise even more difficult scientific and ethical questions. Here, I will discuss various themes that are prominent in discussions of the science and ethics of HHGE, including impacts on human dignity and society, the language of HHGE used for public dialogue and the governance of HHGE.