Under current US regulations, the Food and Drug Administration is banned from considering any studies that would start a pregnancy with embryos that have been genetically modified. But that language has to be renewed every year by Congress—and, last year, the language was briefly dropped before it was ultimately restored. Given the implausibility of a global consensus on how to move the technology forward responsibly, the task will likely fall to individual nations, and it seems unlikely that every country will institute equally strict regulations.

But scientists who hope to move forward with modifying future generations of humans may have more to worry about than just politics. Three separate teams have just demonstrated that Crispr can have catastrophic, unintended effects—like deleting huge chunks of DNA—when used to genetically modify human embryos. While these results have not yet been peer reviewed, they suggest that scientists have a long way to go before they can edit human embryos safely, not to mention ethically.

The Future of Crispr

Despite the arrival of Lulu and Nana, Crispr is still mostly a biologist's buzzword. But just as computers evolved from a nerdy, niche tool for math geeks to a ubiquitous, invisible extension of our own bodies, so Crispr will one day weave seamlessly into the fabric of our physical reality. It will simply be the way to solve a problem, if that problem is remotely genetic in nature.

Take industrial fermentation, for example. With the help of old-school genetic engineering techniques, scientists have already reprogrammed microbes like E. Coli and brewer’s yeast into factories that can make everything from insulin to ethanol. Crispr will rapidly enlarge the catalog of designer chemicals, molecules, and materials that biorefineries can produce. Self-healing concrete? Fire-resistant, plant-based building materials lighter than aluminum? Fully biodegradable plastics? Crispr not only makes all these possible—it makes it possible to produce them at scale.

But we won’t get there with the tools we’ve currently got, which is why researchers are now racing to chart the full expanses of the Crispr universe. At this moment, they’re scouring the globe for obscure bacteria to sequence, and they’re tinkering with the systems that have already been discovered. They’re filing patents on every promising new nuclease they come across, adding to a list that is sure to expand in the coming decade. Each new enzyme will not only advance Crispr’s gene editing powers but also extend its capabilities far beyond DNA manipulation. You see, slicing and dicing isn’t the only interesting thing to do to DNA. Tricked-out new Crispr systems could temporarily toggle genes on and off or surveil the genome to fix mutations as they happen in real time, no snipping required. The first would let scientists treat human diseases where there’s too much or too little of a certain substance—say, insulin—without permanently altering a patient’s DNA. The second could one day prevent diseases like cancer from occurring altogether. The specificity of Crispr, perhaps more than its actual cutting mechanism, will inspire applications we can’t yet imagine.

The Amazing Crispr Enzyme Clan Cas9 | The OG Good at cutting DNA, great for knockouts. Already being replaced by newer base pair editors with more fine-tuned control. Cas12 | The Stickler Like Cas9 but not as sloppy. It leaves “sticky” DNA ends, which are easier to work with when making edits. Cas13 | The Cowboy Cuts RNA, not DNA. Could knock down protein levels without permanently changing your genome. Pair it with a reporter signal and you’ve got a diagnostic. Cas3 | The Gobbler Cas3 gives zero f***. It offers no repair mechanism—once it finds that target DNA sequence it just starts cutting till there ain’t no DNA left. Casɸ | The David Much smaller than its cousins, Casɸ still packs a mighty punch. And its diminutive size means it’s easier to package and send to cells.

As of now, scientists working on the medical applications of Crispr have already achieved some impressive results with real human impact: Victoria Gray, a 34-year-old woman who has struggled with sickle cell anemia for most of her life, just celebrated a year of being symptom-free. To treat her debilitating illness, researchers extracted some of her stem cells, used Crispr to reprogram them to produce healthy blood cells, and returned them to her body. Scientists are working to treat cancer and HIV with a similar approach and have been able to establish its safety—but not, as of yet, its effectiveness.

But none of these trials involved inserting Crispr directly into the patient’s body, because it can be difficult to deliver Crispr to a specific organ or tissue where needles and syringes can’t reach. Though scientists have devised some methods for doing so, these approaches can have potentially harmful consequences: Crispr, when administered in this way, can wreak havoc on portions of the genome where it should never have been in the first place. These unintended modifications, called off-target effects, could theoretically prevent tissues from functioning properly or could jump-start cancers. Figuring out how to limit these off-target effects is a major goal of current Crispr research. And scientists have made some material progress. A team at Johns Hopkins University recently created a light-activated form of Crispr, which can be deactivated to limit its off-target effects. And scientists are experimenting with other approaches for delivering Crispr to particular locations in the body: One individual has even had Crispr injected directly into their retinas in an effort to cure their blindness.

Crispr for the Covid Era It’s no surprise that a biological tool as powerful as Crispr is being leveraged in the fight against Covid-19. The FDA has already issued an emergency-use authorization for a Crispr-based Covid-19 test, which takes under an hour; its designers are also working to create a version that could be administered at home. What’s more, a group at Stanford has developed a Crispr-based treatment that destroyed 90 percent of the virus in test tubes. But like all other potential Covid-19 treatments, this Crispr tool has many regulatory steps to go through before it can see use in patients.

Meanwhile, consumers can expect to see the first Crispr-designed foods lining grocery store shelves very soon. Because Crispr doesn’t use plant pathogens to manipulate DNA (the old GMO-generating method), the USDA has given a free regulatory pass to gene-edited crops, which may allow drought-tolerant soybeans and extra-starchy corn to ease into your favorite processed foods without any additional labeling. Specialty fruits and vegetables will likely follow the commodity crops; the reduced regulatory burden and the cheapness of Crispr will allow companies that prioritize consumers’ senses rather than farmers’ bottom lines to enter the market. Already a dozen or so startups have popped up to challenge the Bayer/Monsanto, DowDupont/Pioneers of the world.