Prospects of Human Germline Modification by CRISPR-Cas9 – an Ethicist’s View

Abstract

Genome editing holds the promise of revolutionizing many fields in which human interventions have hitherto proved to be insufficient to meet major global challenges, like nutrition and environmental protection. However, it is controversial how far this method might also be applied to the human germline with a view to preventing the transmission of serious genetic diseases to offspring. While there is a near-consensus that genome editing, at the present stage of science, should not be applied clinically, it is unclear whether this also extends to clinically oriented research. It is argued that among the arguments against interventions in the human germline there is only one that is sufficiently strong to be practically relevant: The argument that it is doubtful whether the challenge of off-target effects with potentially fatal health consequences can be met. Since nearly all objectives of human germline genome editing can be attained by PGD (except for the rare case of homozygous parents with respect to the relevant genes), there are good grounds for directing clinically oriented research toward the improvement of this alternative method, which has been proven to be without substantial risks and which involves no ethical problems over and above those involved in genome editing.