Scientists could one day create genetically modified 'designer babies’ — but should they?

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This week, the Congressional Research and Technology Subcommittee held its first hearing on the science and ethics of genetically modifying human DNA. The main topic up for discussion was CRISPR, the world's most promising and widely applicable gene-editing technique. So far, CRISPR (pronounced crisper) has been used by multiple labs around the world to modify the genes of organisms as varied as bacteria, plants, mice and some primates. But what lawmakers wanted to talk about with scientists this week is what it will mean when we start making genetic improvements to human beings.

CRISPR is revolutionary in that it lets scientists replace faulty genes with normal ones in a very specific, targeted way. Think about it as a genetic cut-and-paste function. Scientists home in on DNA code they want to delete and then molecularly "highlight" it and swap in the gene they want. Most recently, a group in China used it to reprogram human embryos and remove genes that would cause a blood disease.

That study ramped up an already ongoing debate over the moral and ethical implications of creating "designer babies" and whether and when CRISPR should be used on humans. If you thought the food GMO debate was heated, hold on to your seat. Some scientists had called for a ban on using CRISPR in clinical settings to modify the so-called "germline" — cells in the body involved in reproduction— because those modifications would be inherited by future offspring. What the long-term effects of those changes would be is currently unknown. (Yes, we're basically living through the prequel to X-Men.)


Others have called for more sweeping restrictions that would ban even experimenting with CRISPR in eggs, sperm or embryos. Shortly after the Chinese study was published, the U.S. National Institutes of Health, the government agency that funds much of the country's biomedical research, issued a statement saying it would "not fund any use of gene-editing technologies in human embryos."

But is that really the solution? After all, there are other countries, like China, actively working on CRISPR. And scientists think CRISPR could be one of the most promising possible treatments for genetic diseases like sickle-cell anemia, cancer and Alzheimer's. So, wouldn't it behoove us to try to be at the leading edge of CRISPR-related research, treatments and policies?

Ethical concerns almost always come hand in hand with cutting edge science, so we need to start thinking through them not just abandon promising research. And Congress is starting to do that. During Tuesday's hearing, the Research and Technology Subcommittee members posed tough questions to a group of expert witnesses working in this area: Institute of Medicine president Dr. Victor Dzau; CRISPR pioneer Jennifer Doudna of the University of California, Berkeley; Northwestern University's Center for Genetic Medicine director Dr. Elizabeth McNally and Johns Hopkins University bioethicist Jeffrey Kahn. The experts said the scientific community is still trying to come up with answers.

The National Academy of Sciences has put together an international advisory group to set guidelines on how to assess the safety and efficacy of CRISPR-based treatments and when and how they would be used in humans. The U.S. Food and Drug Administration, the agency that regulates medical treatments, has yet to approve a gene-therapy product, but it's keeping close tabs on CRISPR and how it might be applied clinically, the scientists told the subcommittee. That's reassuring because the first clinical application—likely to be for sickle cell anemia— is just a year or two out, Doudna, who's part of the NAS advisory group, said.


In this case, bone marrow would be extracted from the patient, genetically tweaked to correct the mutation that causes sickle cell anemia and then inserted back into the patient. Because the DNA would be modified outside the body, scientists could easily test if the correct genes were edited by doing DNA sequencing before placing the modified bone marrow back into the patient. Treatments that would require modifying cells inside the body are likely further out because scientists currently don't have a way to target CRISPR to specific cell types or to verify that the editing went as planned.

While the scientific community and regulators will have a lot of say in how these treatments proceed from the lab to the clinic, McNally, the director of Northwestern University's Center for Genetic Medicine cautioned the panel not to forget patient advocacy groups.


"They're going to be the loudest voice in this process, and we have to hear what they want to say," said McNally. After all, patients are the ones that stand to gain—or lose—the most. For the most part, the rules around informed consent will likely stay the same, meaning that clinicians will have to explain the benefits and potential risks of a CRISPR procedure, just like they would any other clinical treatment.

That's all well and good for adults, and perhaps even children, whose parents could explain the treatment to them so they could be made to feel part of the process. But what happens if we decide CRISPR-ing embryos is okay? Today, couples undergoing in vitro fertilization can screen their embryos for genetic abnormalities with a pre-implantation genetic diagnosis (PGD) test and choose not to implant ones that would result in kids with genetic disorders.


In the future, there might be something called pre-implantation genetic correction, whereby doctors biopsy embryos to identify genetic anomalies and then use CRISPR to fix the affected genes. If that genetically tweaked embryo was implanted and birthed by its mother, it would carry those modifications for life. That child's kids would also be affected. Right now, the persons making those decisions would be that would-be child's parents, but is it fair to forever change another's biology without asking?

"How do we think about consent on behalf of someone who hasn't been born?," asked Jeffrey Kahn, the Johns Hopkins University bioethicist.  "Those are the types of questions that need to be…addressed."


Michelle Meyer, the director of bioethics policy at Union Graduate College-Icahn School of Medicine in New York, said that it was worth remembering that at a very high level CRISPR may not be all that different from what humans do already, naturally, when they're making babies. "After all, every decision to create another human being is necessarily made without the consent of that future human being," she told me over email. "When people say that CRISPR poses unusual consent problems, they’re primarily referring to the fact that germline modification means that the changes made will be passed on to future generations. But even this is also true of many other reproductive decisions that we already make: people tend to reproduce with people of the same race, educational background, and socio-economic class, for instance. Some people choose to reproduce despite knowing that they, and therefore their offspring, are at risk for certain diseases."

That being said, she also noted that if CRISPR were to become the standard of care in the future, she "could imagine a wrongful birth lawsuit by the resulting child against his or her parents for failing to cure him or her of a devastating disease through CRISPR treatment at the embryonic stage." Right now, Meyer told me, there is no federal law that prohibits germline genetic modifications for clinical or research purposes, though any attempt to transfer a CRISPR-ized embryo into a woman's uterus would be subject to FDA and NIH regulations. ("Any actor who somehow slips through the FDA/NIH cracks could be liable in tort law for helping to create a baby born with who knows what problems," she added.)


It's true that today CRISPR isn't robust enough to make it a viable option for treating any genetic condition, let alone in situations where those changes would be heritable. But the scientists urged the subcommittee to allow research to proceed because one day these methods could be potentially useful for families.

"We should ban this only with caution," said McNally. "It may be tempting to ban it [completely], but its justified use is certainly conceivable and may one day be appropriate."


Daniela Hernandez is a senior writer at Fusion. She likes science, robots, pugs, and coffee.