According to He Jiankui, an associate professor of bioengineering who is currently on leave from Southern University of Science and Technology, in Shenzhen, China, two “beautiful little” twin girls named Lulu and Nana, the world’s first genetically edited newborns, recently “came crying into this world as healthy as any other babies.” He claims that he used the gene-editing tool Crispr to modify the babies’ genes in order to make them resistant to infection from H.I.V. (Their father is reportedly H.I.V.-positive.) It’s not known whether the claims are true, as He has yet to release any data to demonstrate how he altered a gene that would otherwise allow H.I.V. to enter the children’s cells. Instead, he has posted a series of five YouTube videos about the work. He is also scheduled to speak on Wednesday morning at the Second International Summit on Human Genome Editing, in Hong Kong.
Virtually the entire gene-editing community, including Southern University, has condemned He’s claims. S.U.S. Tech issued a statement saying that the “University was deeply shocked,” that its biology department was unaware of the project, and that it believes that He’s conduct “has seriously violated academic ethics and codes of conduct.” On Monday, a group of more than a hundred Chinese academics and scientists issued a statement calling the research “crazy.” Because the work is still experimental and can pose serious risks, there has been, since 2015, a voluntary international moratorium on editing live human embryos. But the moratorium was never going to last.
In recent years, many institutions have issued admirably high-minded reports denouncing the idea of “rogue” scientists deciding if and when to edit human genes. The phrase “designer babies”—usually used when talking about editing genes with the intent of producing a higher I.Q. or some other seemingly desirable trait—has become a sort of Frankensteinian shorthand. It was wrong for He to carry out this research without even obtaining the approval of his university. But it is even more dangerous to live in a world where few seem to acknowledge that we are moving rapidly into a future where gene editing will be easy and accessible to millions of people.
In one of the YouTube videos, He says that he used Crispr to disable a gene, known as CCR5, that makes a protein that permits most variants of H.I.V. to enter human blood cells. One particular genetic variant of that protein, called the Delta32 mutation, prevents H.I.V. from locking onto a cell. If every person carried that mutation, nobody would get AIDS. In theory, if the father of the baby girls is H.I.V.-positive, disabling the gene would render his children immune to the virus. But there are many unanswered questions about CCR5’s role in the immune system, and about the efficacy of gene editing itself. Genetic editing, with CRISPR and similar tools, has proven immensely promising in the laboratory, with applications from improving the nutrition of basic crops to eliminating infectious diseases, such as malaria, and many congenital illnesses, too.
But no one has previously tried editing embryos that develop into humans, because the science is not yet precise enough to guarantee the results. Crispr is remarkably accurate at editing the genes that it is supposed to edit, but it can also cause off-target mutations. Those accidental edits are far less frequent today than they were even three years ago, but they are still common enough to prevent scientists from attempting to alter the genetics of embryos. Furthermore, once you create embryos that carry permanent and heritable changes to the DNA of humans, or any other species, those changes have the power to alter the composition of that species forever. The risk may be worth considering in order to eradicate one of the many genetic illnesses for which there are no other known cures. But, in the case of H.I.V., there are many ways to both prevent its transmission and to treat it. We don’t need to start by rewriting the human gene pool.
In fact, more than one company is developing a gene-editing therapy that can edit CCR5 in the cells of adults. First, scientists remove blood cells from H.I.V.-positive patients. Then they delete the CCR5 protein and return the edited blood to the patients, so that they can block the virus and prevent its spread. This kind of research has two advantages: it functions as a drug treatment does, and it only affects the genes of the person who is treated. It also makes it possible to provide informed consent. For many people, faced with few options, the potential benefits of trying a new and dangerous therapy will outweigh the risks. But that is a decision that only the person in question can make; it is one that is already made with drug therapy. I am not sure who is qualified to make that decision for all of humanity.
Unfortunately, biology rarely offers simple solutions to difficult problems. Getting rid of CCR5 would prevent H.I.V. infection, but it would also elevate our susceptibility to West Nile virus (and, it appears, to influenza). We know this because there are millions of people who are born without the CCR5 mutation; they are naturally immune to nearly all forms of H.I.V., but they are likely to have a heightened risk of contracting West Nile. Today, that trade-off may seem worth the risk, but there’s no way of knowing whether it will still be a good trade-off seven or ten generations from now. For example, sickle cells evolved as a protection against malaria; the shape of the cell blocks the spread of the parasite. Nobody could have envisioned sickle-cell anemia, but if gene-editing technology had been available two hundred thousand years ago, it might have seemed sensible to edit sickle cells into the human population in order to save it from potential death from malaria. But the results would have been devastating, inflicting sickle cells, which block the proper absorption of oxygen into red blood cells, on much of humanity.
He Jiankui himself has written wisely on the subject, with some of his colleagues, in an article published online on Monday by The CRISPR Journal. The piece, titled “Draft Ethical Principles for Therapeutic Assisted Reproductive Technologies,” cites five core principles for the genetic editing of human embryos: mercy for families in need; use only for serious diseases, never for vanity; respect a child’s autonomy; genes do not define you; everyone deserves freedom from genetic disease. These are admirable guidelines. If only He had spent more time reading them over, he might have skipped this stunt, which will do little to advance human health and perhaps open the way to harming it.