The ethical debate surrounding genome modification has been thrown into sharp relief with the development of CRISPR/Cas9, a genome-editing tool allowing precise modification of DNA sequences. It has already improved our understanding of human disease, but what is most exciting is its therapeutic potential. CRISPR technology allows the possibility of treating human disease by directly editing and correcting genetic mutations in affected cells. However, the potential for making heritable alterations to the human genome has generated widespread discussion and rekindled the ethical debate on human germline modification. To help broaden the discussion of the ethical concerns that emerge from editing the human genome, I would like to add some perspectives from Jewish bioethics.
Jewish bioethics emerges from the practical application of Jewish law to ethical questions in contemporary medicine. A central tenet of Jewish law, which takes precedence over virtually all other religious commandments, is that a human life has infinite value. The duty to help heal the sick and prevent disease is so overriding that the Mishnah, the oral law, says: 'He who saves one life, it is as if he saved the whole world.' This moral imperative to restore health and prevent disease is therefore a fundamental starting point in Jewish bioethics.
As with any medical innovation, there are questions of safety. The most obvious concern is that of 'off-target' mutations – when unintentional edits occur at other locations in the genome because of similarities in the DNA sequence, with potentially harmful side effects. But, while serious, this concern is more technical than ethical per se.
As a therapeutic tool, genome editing has enormous potential, allowing the possibility of avoiding genetic diseases. This, and the lack of existing therapies, provides a medical case and ethical support for this technology. It is also the only option if a couple with a genetic disease produce a single affected embryo. Most profoundly, germline genome editing allows the birth of a child who is not a carrier of the condition, therefore reducing the frequency of disease in future generations.
Genome editing has the remarkable potential to prevent genetic diseases being passed on to future generations, but also comes with the risk of inheriting unexpected detrimental effects. This is in sharp contrast to other medical interventions, which affect only the individual at hand. Here, if things go wrong it will affect all future generations. However, a clear distinction can be made between the clear and present danger associated with off-target mutations and these potential unknown risks to future generations. An oft-used principle from the Talmud, the elucidation of Jewish oral law, is that 'a certainty wins over a case of doubt'. Applied here, this would provide an argument in favour of using genome editing with a couple facing the birth of a child with a devastating disease, like Tay-Sachs, over potential unknown risks in the future.
One of the biggest ethical concerns around genome editing is that it will be exploited for unnecessary human enhancement through so-called 'designer babies'. The morality of enhancement, and determining when an intervention crosses the line from being therapeutic to non-therapeutic, is subjective and open to differences in social and cultural norms. But, from a Jewish bioethical perspective, the argument for permitting genome editing rests on the moral imperative to restore health and prevent disease. Once an intervention is no longer therapeutic this moral imperative is removed, and with it the possibility of outweighing the ethical and safety concerns.
It is very important to place new technologies in the context of existing technology and legal frameworks. There is little benefit in comparing genome editing to an idealistic world with little human intervention. Humans have eradicated diseases, used technologies like pre-implantation genetic diagnosis (PGD) to screen for and avoid genetic disease, and have recently successfully created so-called 'three-parent babies' using mitochondrial donation. All those technologies carried risks along with benefits. In this context, it is difficult to argue that genome editing is so different, that it crosses an ethical red line or radically changes the course of human evolution in a way that no other medical advancement has.
There is always risk, and we must appreciate our limited understanding of genomics. Recent advances in our understanding of genetics, such as transgenerational epigenetic inheritance, suggest it would be wise to tread carefully. The potential for misuse of genome editing is not a justification against the development of the technology or its therapeutic use, but does make critically important the establishment of a robust regulatory framework to ensure that genome editing is performed appropriately. From a Jewish bioethical perspective, the enormous potential of genome editing as a therapeutic tool provides strong support for the moral imperative to continue research.
On Wednesday 7 December 2017, genome editing and embryo research will be debated at the Progress Educational Trust's public conference 'Rethinking the Ethics of Embryo Research: Genome Editing, 14 Days and Beyond'.