For thousands of years, we have been trying to craft our ideal canine companions. We have honed their abilities to perform an array of specific tasks, from fetching waterfowl to staring down wayward sheep. We have reshaped and refined their bodies, producing sausage-shaped dachshunds, polka-dotted Dalmatians, bushy-browed schnauzers and deeply wrinkled Shar-Peis.

And we have done it using nothing more sophisticated than good old-fashioned selective breeding.

Now our canine engineering efforts are entering a new era. Earlier this month, Kindred Companion Sciences, a biotech start-up based in New York, revealed that it had used the technique known as CRISPR to create the first gene-edited, hypoallergenic dogs. Thanks to a single genetic tweak, the dogs — two undeniably adorable beagles — appear unable to produce a protein that can leave some people red-eyed and wheezing.

Still, it’s a long way from the lab to the laps of pet owners across America. (It’s been two and a half years since scientists announced a gene-edited, hypoallergenic cat, but such felines are not yet available to the public.) More time and data are needed to determine whether Kindred has truly delivered on its promise of hypoallergenic dogs, experts said. Can a single gene edit reliably stave off the sniffles in humans?

An even more critical question: What does it mean for dogs? Will our efforts to create pets that are more convenient for us have unintended health consequences for them?

History is not encouraging. Since the Victorian era, when dog fanciers began to create and codify modern dog breeds, our quest for the perfect pooch has yielded dogs that are inbred, disease-prone and saddled with extreme physical traits — super flat faces and ultra long backs — that compromise their welfare.

“We’ve created an enormous amount of inherited diseases in dogs, often unintentionally, because of our pursuit of certain traits that appeal to us,” said Rowena Packer, an expert on companion animal welfare at the Royal Veterinary College in London. “I just think we have a lot more responsibility to think more critically about the dogs that we create.”

Dog design

For all the canine diversity we’ve managed to create through selective breeding, a truly hypoallergenic dog remains something of a holy grail. Breeders have created all manner of low-shedding dogs and purportedly hypoallergenic dogs (behold the labradoodle and all of its doodle-y descendants). But these dogs still produce proteins that, secreted through their skin, saliva and urine, can trigger human allergies.

Gene editing provides a “simple, elegant” way to solve the problem at the source, said Matt Walker, the co-founder and chief executive of Kindred, who has suffered from dog allergies his whole life.

Kindred began with canine cells, using CRISPR to disable a gene known as Can f 1, which codes for one of the main canine allergens. Then, the scientists used a basic cloning technique to transfer the edited genomes from these cells into dog embryos. They implanted the embryos in a surrogate beagle mother, who gave birth to two puppies: Alfie and Bailey, who are now almost 2 years old.

The company has detected no trace of the allergen in either dog, and Dr. Walker, who adopted Bailey, has experienced no allergic reactions. (Alfie was adopted by one of Dr. Walker’s colleagues.) The dogs appear to be developing normally.

“No red flags, no yellow flags — so far, the animals seem completely healthy,” Dr. Walker said. “That said,” he added, “this is the starting point of our work.”

Indeed, for all its purported precision, gene editing can have unpredictable consequences. Medical issues might appear later in the dogs’ lives, or when the company starts producing enough dogs to spot rare side effects.

Or, of course, they could turn out to be perfectly healthy. But it’s too soon to say, and we’re likely to see more efforts to create gene-edited dogs in the future. Where do we want to draw our ethical lines?

Thirty years ago, when genetic engineering was still in its infancy, the philosopher Bernard Rollin proposed an ethical principle he called the “conservation of welfare,” which held that we should not modify animal genomes in ways that left the animals “worse off, in terms of suffering” than their unmodified forebears.

That’s a sensible starting point. But it’s a low bar. And it doesn’t address all the ethical implications of making gene-edited dogs, which may require using additional animals to serve as test subjects, egg donors and surrogate mothers.

“I think we get sometimes so excited about the idea of what technology can fix, particularly biotechnology — we’ve got to remember that, generally, we use a lot of animals to get to that end ‘product,’” said Dr. Lisa Moses, a veterinarian and bioethicist at Harvard University.

Ethicists have also questioned whether we should bring gene-edited dogs into a world that already has more dogs than it can care for, especially when the goal is not to create a healthier animal, but one that better meets our human needs.

“Should we use sophisticated biotechnology to create the animals we want, rather than changing how we relate to the animals who already exist?” said Jessica Pierce, a bioethicist at the University of Colorado Anschutz Medical Campus. “That’s a question of priorities, and perhaps misplaced priorities.”

Dr. Walker sees it differently. His allergies would prevent him from ever adopting a shelter dog, he said; gene editing is the only thing that has made it possible for him to have a relationship with dogs. “I’m also really invested in applying this work to service dogs for people who are allergic,” he said.

“People’s ethical barometers are set differently,” he added. “For me, this feels justified by the potential benefits, as long as animal health is protected.”

Good breeding

Dog lovers can, in good faith, come down on different sides of the Kindred question. But if we’re going to discuss the ethics of dog creation, experts agreed, we need to ask ourselves some hard questions not just about our new gene-editing tools, but also about our longstanding breeding practices.

“At the end of the day, they’re both producing animals for companion purposes,” said Alison Van Eenennaam, an expert on animal genomics and biotechnology at the University of California, Davis. “It’s not the technology that’s creating the ethical issues.”

We’ve done plenty of harm without modern biotechnology. And there are ways to use gene editing to improve canine lives — even, in some cases, to undo some of the damage done through selective breeding. In a 2022 study, scientists showed that it was technically possible to use gene editing to “correct” a genetic mutation associated with hip problems in Labrador retrievers.

But these hip problems stem from a variety of risk factors — both genetic and environmental — and most canine health conditions probably cannot be cured by editing just one gene, experts said.

Improving dog welfare is likely to require an array of complementary approaches. These include revising breed standards, opening up closed breeding pools, performing widespread genetic screening and educating the public about the welfare costs of breeding dogs with certain physical traits.

Experts have been calling for these reforms for years, with limited success. But they are necessary if we want to bring our behavior in line with the values we claim to hold. We are, after all, a society that is so besotted with dogs that we have start-ups trying to develop canine longevity drugs — and editing genes so that people can live alongside creatures that would otherwise give them hives.

Life with Bailey has been “amazing,” Dr. Walker said. “I didn’t really appreciate, when people say pets are part of your family, what that really means. But she really is a part of our family.”

His wife had grown up with dogs, he added, and had long bemoaned his allergies. “She always said that this was the one thing she wished she could change about me,” he said.

Indeed, as news of Kindred’s hypoallergenic dogs spread across the internet this month, one Facebook commenter raised precisely that possibility: “Why doesn’t he alter himself instead of the beagles?”

Alas, we can’t yet edit dog allergies out of our own genomes. But that doesn’t mean we can’t evolve.