In recent years, new genome editing technologies have sparked rapid growth in the genetic sciences. In particular, the development of CRISPR gene editing opens the door to a host of potential benefits, from agricultural improvements to disease eradication. This powerful, inexpensive and efficient tool allows scientists to tackle medical challenges that had previously proved unsurmountable.
However, CRISPR-Cas9 use in humans also raises ethical concerns. That’s because, along with therapeutic applications, gene editing technology may be used to enhance or alter human traits. This potential opens a Pandora’s box of questions, sparking debate around the ethics of genome editing; how should the practice be governed? What’s the scope of responsible use?
A widely publicized case of gene editing in human embryos — and the resultant prison sentences doled out to the researchers involved — underscores the gravity of these questions. The dialogue surrounding the ethics of CRISPR gene editing continues.
Somatic and Germline Gene Editing
What makes CRISPR so ethically fraught? Some concerns stem from the distinctions between two types of gene editing: somatic and germline. Somatic editing affects only the individual being treated, and only a portion of their cells. In contrast, germline editing affects all cells, including reproductive cells. This means alterations may be passed down through future offspring. This means ensuing changes are unpredictable.
CRISPR is used for somatic gene editing. For instance, a person with a disease caused by a genetic mutation might benefit from CRISPR; the technology could be used to correct the mutation, then re-introduce the altered cells. In this scenario, only that individual’s “defective” cells would be affected, and they would not pass the changes along to any future offspring.
CRISPR may also be used for germline gene editing. In such cases, any genetic changes would be passed down to future offspring, affecting them, their descendants, and so on. This impacts not just the initially treated individual, but many others down the line. That’s why restrictions on germline gene editing historically and currently exist.
But not all scientists agree on blanket restrictions. Some call for a rethinking of categorical prohibitions on germline editing, given CRISPR’s therapeutic potential and in light of improved accuracy.
Tricky Ethical Questions
These ethical questions took center stage in 2018, when Chinese researcher He Jiankui announced that he’d used CRISPR to modify the CCR5 gene on two human embryos, increasing resistance to HIV. Both of the babies were carried to term.
The outcry from the scientific community was immediate. Consensus pointed to a condemnation of He’s actions as a violation of ethical norms. He and two colleagues were ultimately incarcerated and fined, which has (thus far) had a deterrent effect on similar germline work.
However, the He Jiankui case didn’t stop all such work. Similar research is planned in Russia, and some researchers argue the potential therapeutic benefits of CRISPR technology far outweigh ethical concerns about germline editing. In fact, some in the field posit that the truly unethical path lies in not using gene editing to improve human health prospects, even framing it as a “moral imperative.”
But others maintain that innovations, no matter how effective, can’t supplant potential issues in areas such as human rights, dignity and informed consent. As a new technology, there’s also the issue of unintended and unknown consequences on future generations. And, of course, there’s also the worst-case consideration of CRISPR use for eugenic purposes.
While there are no easy answers, one thing is certain: Discussions of the ethical questions surrounding CRISPR gene editing must take into account these nuanced and complicated distinctions.