Gene editing has the potential to treat a variety of diseases, rare genetic diseases that affect only a few people as well as common diseases that affect millions of people. There is enormous potential for benefit for living patients suffering from disease.
One example is patients with heart disease or at high risk for heart disease. Gene editing could permanently turn off cholesterol genes in the liver, resulting in reduced cholesterol levels and protection against heart attacks and stroke. It would be like taking a cholesterol-lowering statin drug, a pill every day for the rest of one’s life, but with a single injection. It would be a “one-and-done” therapy, like a vaccination against heart disease.

Recently it was announced that a CRISPR therapy was able to treat two patients with sickle cell disease or beta thalassemia, devastating blood disorders. The early signs are that the patients might actually be cured. I think we will see CRISPR successfully applied to a variety of common diseases—cancer, AIDS, and heart disease, to name a few—in the next few years.

He Jiankui acted irresponsibly on many levels. His attempts to make gene-edited babies were done in secrecy, without oversight and without transparency. He believed he had enough mastery of gene-editing technology that he could do everything on his own, but he did not. In sloppily using CRISPR in embryos, he inadvertently caused genetic damage to the embryos he used to establish a pregnancy that resulted in two live-born girls. The girls almost certainly have genetic damage in their bodies, and they are at risk at passing the genetic damage to their own children. Finally, he broke pretty much every principle of medical ethics in the textbook. This was both a scientific disaster and an ethical disaster, resulting from arrogance and incompetence.

Yes. CRISPR technology is not ready for use in human embryos. There are serious safety issues that will take years to solve, if ever. He Jiankui showed just how badly things can go wrong.

There are three possible scenarios. In the first scenario, the parents have medical issues that make it impossible for them to have healthy biological children without gene editing. These are rare cases, but they exist. In the second scenario, parents might wish to reduce their child’s risk of a serious disease in their lifetime—breast cancer, Alzheimer’s disease, and heart disease, to name a few. There is no guarantee that the child would have developed the disease for sure, and there is no guarantee the editing will completely eliminate the risk of disease, but the parents would be stacking the odds in their child’s favor. The third scenario is non-medical enhancement, ranging from cosmetic changes like eye color and hair color to more substantial things like intelligence and athletic ability.

It is up to each person to decide for themselves which of these scenarios are acceptable and which are not. Some people would reasonably argue that none of these scenarios are acceptable, because parents always have the option to adopt children or to use sperm cells or egg cells from healthy donors.

Adult patients suffering from a disease have the ability to freely consent for a medical procedure as long as they understand the benefits and risks of the procedure. A gene-editing therapy would relieve their suffering. The therapy would also be directed only to the organ involved in the disease (blood, liver, heart, etc.), not the entire body, and there would be no possibility of passing any edits to children and future generations.

For gene-edited babies, the editing would probably be done in an embryo created by in vitro fertilization or in sperm cells or egg cells. There is no possibility for the future person to consent to a procedure done long before their birth. Furthermore, an embryo or sperm cell or egg cell cannot be said to have disease; disease only occurs later. For parents, there would have to be a positive choice to have a baby, with a risk of disease; the parents could avoid the situation by simply not using an embryo for pregnancy. Finally, because an embryo starts with a single cell that divides and becomes all of the cells in the person that is born, any edits will be in every single part of the person’s body—including that person’s sperm cells or egg cells. This means the edits could be passed on to that person’s children and to future generations. So it does not just involve a single person, but potentially many people.

The public is generally supportive of gene-editing therapies for adult patients, because of the potential to relieve suffering. It is more complicated when it comes to gene-edited babies. There is majority support for a scenario in which gene editing is needed to have a healthy baby, and very little support for enhancement. People are much more sympathetic to parents who would not be able to have a healthy biological child without gene editing than they are to parents who would use gene editing to try to make their child better than everybody else’s.