In November, a Chinese scientist named He Jiankui made an announcement that many in the gene-editing community had been expecting—albeit dreading—for years: He’d secretly edited the genes of embryos that were now living, breathing humans, crossing ethical boundaries to prove that Crispr, the buzzy technology that promises to transform medicine and agriculture, can also easily be applied to us.
The moral dilemma soon dominated headlines: If you edit the human germline—the genetic blueprint carried in sperm, eggs, and embryos—those changes are duplicated in all cells made from those original cells, and passed on through reproduction. That means Crispr may have the power to eradicate diseases such as cystic fibrosis, sickle-cell anemia, hemophilia, and Huntington’s disease, which are all caused by a faulty gene. It also means that the era of “designer babies” could soon be upon us. While parents are, say, altering genes from their embryos that are linked to cancer, they could also be tempted to tweak the genes that control simple traits like eye, hair, or skin color. In the future, they might be able to enhance their children’s intelligence, meaning that those who could afford to have their kids Crispered would have huge advantages over those who couldn’t.
He’s announcement brought attention to the reality that tweaking future humans with Crispr is well within the capabilities of thousands of labs and fertility clinics, and that governing them all is going to be very hard.
What many discussions of this awesome power often leave out, however, is that no matter what rules we build up to govern Crispr—even if we ban all Crispr research on human embryos, as some advocates have proposed—designer babies are on their way to becoming the norm. Because while Crispr is often portrayed as the gateway to designer babies, in fact, there’s a much more likely path that is already well underway and all but inevitable.
It starts with a procedure called Preimplantation Genetic Diagnosis (PGD), which has become an increasingly common part of in vitro fertilization (IVF). With normal IVF, doctors produce multiple embryos from a couple’s sperm and eggs and then implant one. With PGD, they first sequence the DNA of those embryos to decide which one to implant.
Traditionally, PGD has been offered to people with serious genetic diseases. If you have Huntington’s disease or sickle-cell anemia, PGD allows you to pick an embryo that hasn’t inherited the bad gene. It’s been useful only for single-gene diseases or other obvious traits (such as gender, where its use is controversial but increasingly common), but our ability to read embryonic DNA and predict complex traits from it is improving rapidly, and PGD can now tell you an extraordinary amount of information about your child-to-be.
For instance, Genomic Prediction, a New Jersey startup in the field of reproductive medicine, can not only screen your embryos for simple genetic diseases, it can also flag embryos with an unusually high risk of complex ones, including diabetes, heart attack, coronary artery disease, breast cancer, prostate cancer, skin cancer, ovarian cancer, high blood pressure, and more. It can even test for what it calls “idiopathic short stature” (i.e., really short) and “intellectual disability” (really dim). For the time being, the startup says that when it comes to height or intelligence, it will only screen out embryos that are likely to be highly deficient in either category, but it can just as easily flag the really tall and the really smart. If other companies around the world begin offering such services, and people demand it, other clinics may follow suit. Considering the fortunes parents already spend on private schools and SAT tutors, it is likely to become an industry of epic proportion.
At least one million babies, in the US alone, have been born with the help of IVF or other lab-assisted techniques. That number could explode once researchers perfect a new technique that allows them to make eggs from a woman’s regular skin or blood cells (something they have already accomplished in mice), which will make IVF much less expensive and invasive.
Once that happens, PGD may become an option every couple considers. And as the PGD kids excel, it will be hard not to jump on the bandwagon. There will always be couples who have their kid the old-fashioned way, with no foreknowledge of potential problems, but such a choice may eventually be seen as irresponsible, something already happening with other prenatal testing.
Many of the fears around Crispr cannot yet be realized with Crispr. Making the thousands of DNA changes necessary to influence a trait like intelligence, for instance, is well beyond our capabilities. But with PGD, we don’t need to rely on Crispr in order to influence the intelligence of future generations. We can just keep selecting the smartest embryos. No gene editing required.
I do think Crispr and other gene-editing techniques will eventually play a role. Once an embryo has been chosen, we might use gene editing to “clean up” any lingering, single-gene issues. This option will allow people to choose from all embryos, rather than throwing out the ones that inherited problematic genes. It may become as automatic as vaccinations.
I know how creepy this sounds. It opens up huge ethical chasms society will need to cross carefully. Beyond the issue of haves and have-nots, it might raise expectations on children unbearably. If your DNA says you should shine, there’s no excuse not to.
But I think it will happen. The marketplace, and human nature, will ensure it, and the improvements in health will be a tremendous good. While it’s tempting to enact rules in an effort to prevent designer babies, doing so risks driving this science underground into shadowy labs like He Jiankui’s. We do have time to get it right—and accepting that some genetic editing in humans is inevitable is the best chance we have of making sure it’s as positive, equitable, and acceptable as possible.