The Interesting Science And Ethical Concerns Behind CRISPR-Cas9

A simple overview of how CRISPR-Cas9 gene editing works (via iotaSciences).

Recent innovations in biotechnology have enabled us to do something remarkable: change the very building blocks of life. A revolutionary scientific instrument, CRISPR-Cas9 allows scientists to cut, modify, or replace DNA segments, unlocking medical miracles that were inconceivable just a decade ago. With it, we can treat genetic diseases and even rewrite the very human blueprint. However, this raises an ethical dilemma that we’re nowhere near ready to answer: should we redesign life just because we can? To ponder this question, we must first look at the science behind genetic editing, recent developments that test its limits, and what a future with this technology could mean for society as a whole.

The Science Behind Genetic Editing

Developed in 2012 by scientists Emmanuelle Charpentier and Jennifer Doudna, who were awarded the 2020 Nobel Prize in Chemistry for their work, CRISPR-Cas9 acts almost like a pair of scissors. Scientists use it to snip out bad genes and replace them with brand-new, healthier versions. CRISPR has been experimentally used to remedy conditions like sickle cell anemia, muscular dystrophy, and even some forms of cancer. 

Then, in December 2023, the FDA approved the first certified CRISPR-based therapy, CASGEVY, to treat sickle cell disease and beta-thalassemia. This treatment works by extracting a patient’s blood-forming stem cells, editing the faulty gene responsible for the disease, and then reinfusing the corrected cells back into the patient’s body. In doing so, it provides a one-time, potentially lifelong cure that eliminates the need for dangerous blood transfusions and reduces the risk of painful symptoms.

Newer developments in the field take this to the next level. Unlike standard CRISPR-Cas9, which cuts both strands of DNA, base editing chemically changes a single base in the DNA without cutting through the entire DNA strand. This more efficient process can better correct single-gene disorders such as cystic fibrosis, Tay-Sachs, and Huntington’s disease.

The Ethics of Engineering

However, as technology enables us to intervene more and more in these matters, we are confronted with the challenging question of how to do so ethically. Most of the current focus in the genetic field is on somatic cell editing, which targets non-reproductive cells to cure diseases in an individual. However, the possibility of germline editing—altering embryos or reproductive cells so that changes are passed to future generations—has raised many eyebrows.

The first central ethical quandary is about agency and consent. When gene editing is done on an adult, it’s one thing. However, when editing an embryo’s genes, the person has no say in the modifications made to their body and identity. As bioethicist Françoise Baylis writes in her book Altered Inheritance, “The person most affected by a germline intervention has no voice.” As a result, scientists often argue that this technology would infringe on bodily autonomy rights.

In addition, where do we draw the line between curing diseases and enhancing traits we deem desirable? Treating Huntington’s disease or cystic fibrosis may seem like a good use of this technology, but is it okay to use the same tools to increase height, intelligence, or athletic ability? The notion of designer babies is no longer a figment of imagination or something you would see in a sci-fi movie. Many ethicists worry this could legitimately reawaken eugenic ideologies that seek to “perfect” the human species. In a 2023 Pew Research survey, 65% of Americans supported gene editing for treating serious diseases. However, only 14% supported it for enhancing intelligence. This disparity in public opinion reveals a broader discomfort with using technology for non-medical enhancements. These tools can potentially contravene the values underpinning our definitions of health and normalcy.

Another concern is inequality. Make no mistake: advanced gene-editing therapies are expensive. CASGEVY treatments are expected to cost around $2 million per patient. Such therapies may only be accessible to the ultra-wealthy, exacerbating existing disparities in health care. If only the privileged can afford to prevent genetic diseases or enhance their children’s capabilities, the genetic divide could perpetuate cycles of social inequities.

On top of all of this, one of the most basic arguments against germline editing is the unpredictability of genetic interactions. Human DNA is highly complex, and editing one gene could trigger unintended effects across the genome. Changes may appear safe now, but we don’t know what could happen years later. For example, in 2018, Chinese scientist He Jiankui used CRISPR to edit the CCR5 gene in embryos, making them immune to HIV. Because of the lack of knowledge about what these interventions could mean, the resulting birth of gene-edited twins led to global outrage. In 2020, Jiankui was sentenced to three years in prison, and his experiment was a wake-up call to the scientific community.

The Need for Regulation

Many countries have adopted strict regulations or moratoriums on germline editing in response to the concerns. The FDA prohibits germline editing for reproductive purposes in the U.S., and the European Union maintains similar restrictive policies. The World Health Organization (WHO) has called for an international registry of gene-editing trials and urged governments to establish oversight bodies to ensure transparency and integrity. Still, enforcement isn’t always stringent enough, and there is a potential for rogue experimentation. Some ethicists, like Julian Savulescu from Oxford University, support a cautious approach. He states, “We have a moral obligation to pursue genetic editing to alleviate suffering but only under strict ethical scrutiny and public engagement.”

The Future Is in Our Hands

The power to rewrite the human genome may be the most significant scientific breakthrough of the 21st century. It has the potential to cure disease, extend life, and redefine what it means to be human. But while it may be exciting, it also invites scientists to address a host of questions: What does it mean to be natural? Who gets to decide what a good life looks like? What do we owe future generations? However, the conversation about gene editing cannot be left to scientists alone. Ethicists, policymakers, educators, patients, and the public must weigh in as well. In the words of philosopher Hans Jonas, “The imperative of responsibility is to act so that the effects of your action are compatible with the permanence of genuine human life.” As we begin to edit the very code of life, we need to ensure that we are doing so ethically and carefully.