The DNA of early human embryos carrying a sequence leading to hypertrophic cardiomyopathy—a potentially deadly heart defect—has been edited to ensure they would carry a “healthy” DNA sequence if brought to term. The Nature paper announcing this has reenergized a terrific national and international debate over whether permanent changes in DNA that can be passed from one generation to another should be made. Bioethicists are asking, “Should we genetically engineer children?” while some potential parents are almost certainly asking, “When will this technique be available?”
The “Should” questions bioethicists are asking are probably not relevant. The only question whose answer ultimately matters is: “Can techniques like CRISP-R be used to genetically engineer children safely?” Because a variety of forces guarantee that if they can be, they will be.
The key questions reliable practitioners must answer are: “Can we prove it works?” Then: “Can it be used safely?”. If “yes” on these questions, then we will see: “Who is marketing this technique to potential parents?” Finally, we will learn: “Where was it done, who did it, and who paid for its use?”
We are closer than ever before to using CRISP-R to replace dangerous DNA sequences with those that won’t keep a baby from being healthy. Fortunately, this Nature paper leaves many questions Unanswered because the embryos were not allowed to come to term.
Most importantly, we still don’t know “Could the embryos have developed into viable babies?” Just as in 2015 when researchers at Sun Yat-Sen University in China didn’t implant engineered embryos into a woman’s womb, the scientists who published in Nature recently didn’t feel ready (and didn’t have permission) to try this potentially enormous step. As experiments proceed, this question will, at some point, be answered.
It will be answered because there is an enormous, proven market for techniques that can be used to ensure that a baby will be born without DNA sequences that can lead to genetically-mediated conditions; many of which are devastating as we have been tragically reminded of late.
Under the best circumstances, in-vitro fertilization leads to a live birth less than half of the time. As a result, whoever tries to see if an embryo that has had targeted DNA repaired using CRISP-R will doubtless prepare a lot of embryos for implanting in quite a few women. When those women are asked to carry these embryos to term we will not know about it. We will probably not find out if none of the embryos come to term successfully.
We *will* know about this procedure if even one baby comes to term and is born with the targeted genetic sequence corrected as intended. Until now, (and maybe even with our new knowledge), any baby brought to term after CRISP-R was used to edit and replace unhealthy DNA would have almost certainly had other DNA damaged in the editing process. This near-certainty and other concerns have held people back from trying to genetically engineer an embryo that they would then bring to term. They could not, until recently, have confidence that only the sequence being targeted has been affected. With this new Nature report, this, at least, is changing.
The results of these newly reported experiments are many steps closer to “usability” than the Chinese experiments reported in 2015. This is the nature of scientific experimentation, particularly when there is demand for the capability or knowledge being developed.
People try something. It either works or it doesn’t. Sometimes when it doesn’t work, we learn enough to adjust and try again. If it does work, it often doesn’t function exactly the way we expected. Either way, people keep trying until either the technique is “perfected” or it ultimately proves to be unusable.
This Nature paper is an example of trying something and doing a better job than the first attempt. It does not represent a provably safe and reliable technique …. Yet. If market driven research works as it often does, people will work hard to publish data (hopefully from reliable experimental work) suggesting they have a “safe and effective” technique. Doing so will let them tell some desperate set of wealthy prospective parents: “We should be able to use this technique with an ‘acceptable’ chance of giving you a healthy baby.”
Princeton’s Lee Silver predicted parents’ desire for gene editing in his Remaking Eden, a book published in 1997. He argued this because people fear sickness or disability and feel strong personal, economic and social pressures to have healthy, “beautiful” children who should become healthy “attractive” adults.
People already spend a great deal on molecular techniques like pre-implantation genetic diagnosis (PGD). PGD is regularly used to reduce couples’ risk of having babies with known (or potential), chromosomal abnormalities and/or single gene mutations that can lead to thousands of DNA-mediated conditions.
As I showed in my Genetics dissertation published from Yale in 2004, different countries respond differently to “controversial” science like this. Similarly, different individuals’ responses are equally diverse. One poll indicates nearly half of Americans would use gene editing technology to prevent possible DNA-mediated conditions in their children. Policy makers who object to the technology therefore have a problem: if they succeed in blocking it somewhere, research and real world experience indicate other governments may well permit its use. If this happens, these techniques will be available to anyone wealthy and desperate enough to find providers with the marketing—and hopefully scientific—skill needed to sell people on trying them.
This gene editing controversy is a reminder that we are losing the capacity to effectively ask, “Should we?” As our knowledge of science grows, becomes more globalized, and is increasingly easy to acquire for people with different morals, needs and wants, we must soon be ready to ask, “Can we?” and ultimately, “Will someone?” Their answers will give us the best chance to ensure any babies that may come from any technique described as “genetic engineering” are born healthy, happy, and able to thrive.