A new dog breed has waddled its way into Americans’ hearts. While Labrador retrievers were the most popular purebred dog for a record 31 years, French bulldogs—or “frenchies” as they’re called by enthusiasts—took the top spot in 2022 for the first time, the American Kennel Club announced on March 15.

But the selection doesn’t come without some controversy. Veterinarians have long warned that the breed’s popularity is contributing to their suffering. Like other dog breeds with scrunched faces, such as pugs and bulldogs, Frenchies are plagued by a range of health problems tied to their distinctive shape. And as their popularity has risen and the price of a puppy has soared into the thousands of dollars, veterinarians have warned that there’s an incentive to breed more dogs at the expense of their health.

Compared to many other purebred dogs, French bulldogs are unusually susceptible to certain health conditions, including spinal problems, difficulty giving birth and issues with their skin. One of the most serious issues is “Brachycephalic Obstructive Airway Syndrome (BOAS),” which makes it difficult for the dogs to breathe. While some dog owners may dismiss it as normal for French bulldogs to snort and wheeze, veterinarians warn the condition harms the quality of dogs’ lives and is associated with health problems, such as gastroesophageal reflux, sleeping problems and hypertension, and can require lifelong health maintenance, including surgery. According to one study, French Bulldogs are about 31 times more likely to suffer from obstructive airway syndrome than other dog breeds.

Some airlines, including American, have even banned all bulldogs and other snub-nosed dog breeds from their cargo holds as a result of the pups’ respiratory issues.

As French Bulldogs have become more popular, the number of dogs with BOAS has also increased, warned Dr Peter Sandøe, director of the Centre for Companion Animal Welfare at the University of Copenhagen, in a statement through the World Small Animal Veterinary Association (WSAVA) released in February. The WSAVA said that the popularity of short-nosed dogs has led to a “canine welfare crisis.”

“Selective breeding for an exaggerated short nose has created dogs whose health, in many cases, is compromised for the sake of perceived ‘cuteness.’ It is simply unethical to breed dogs which struggle to breathe,” said Sandøe.

Some animal organizations and welfare advocates have pushed for better breeding practices to protect the health of French bulldogs and other pups. In 2021, the United Kingdom’s kennel club updated its standard for French bulldogs to encourage breeders to avoid exaggerated features that could harm their health, and breed for a “well-defined muzzle” with visibly open nostrils.

The WSAVA urged breeders to prioritize producing animals without health issues, including by screening animals to ensure that they can breathe, or to test if they can go for a three-minute walk without laboring to breathe.

Following the 2021 announcement of the new standards, Dr. Laura Hamilton, a veterinary surgeon in the U.K., said in a statement through the kennel club that pet owners should be aware of the dogs’ health problems.

“These days social media can often be influential on the way that dogs are bred to look, so we urge any would-be owners to fully research the breed before making any decisions, speak to experts, and find a responsible breeder who health screens their dogs,” she said.