Millennials are raising pets instead of kids. It's not going well for the pets.

Yena Kim describes her Shiba Inu, Bodhi, as her "soul dog." She hadn't planned to get a dog, but when she held him for the first time 15 years ago, she knew he was special. "I truly believe that we were meant to meet," Kim, now 37, says. "He was meant to be my muse and inspiration."

Ten years ago, Kim was working what she calls her dream job at Ralph Lauren when she decided to quit so she could spend more time with Bodhi. "It killed me to see his sad face as I left home for work," she says, "so I designed a new job where I can spend all day with him."

Menswear Dog was born. The social-media brand features Bodhi modeling menswear outfits that Kim makes. For a couple of years Kim built the account on nights and weekends while working a day job as a marketing consultant so that she could afford a place in Brooklyn with a yard for Bodhi and her other dog, Luc. She even went without health insurance for a while to make sure the dogs were taken care of. (The pups always had insurance.) Now she earns enough from Menswear Dog to focus on it — and her dogs — full time.

"Bodhi and Luc have forged a path for me and with me," she says, adding that taking care of her dogs has given her an "immediate sense of purpose."

She isn't the only millennial who feels this way about her pets. The generation is leading the way when it comes to pet ownership — almost a third of US pet owners are millennials. And they adore them: In an online survey of American pet owners in April, more than a third of millennial respondents said they'd turn down a higher-paying job to spend more time with their animal companions.

The rise in pet ownership stands in stark contrast to another recent trend: the decline in parenthood. The percentages of US women between 30 and 39 in 2022 who had never had children were the highest they'd been since at least 1976. As more millennials move away from traditional family structures, adopting a pet has become a new milestone. As a result, millennials are increasingly spending time and money pampering their animals. A MarketWatch report said pet spending increased by 67% from 2013 to 2021, and businesses including dog cafés and luxury cat hotels have emerged to cater to the growing demand. But pet trainers and veterinarians say excessive pampering may be leading to health and behavioral problems.

A recent study published in The Lancet predicted that by 2100, more than 97% of countries and territories will have fertility rates below the levels needed to sustain their populations. Meanwhile, the number of people with pets continues to climb. In China, whose population has been shrinking, the urban pet population is expected to surpass the country's number of toddlers by 2030.

Hayley Kellard lives in the UK and has never had much interest in having children. The 40-year-old says she's happy being child-free — but when it comes to dogs, it's a different story. Kellard's family has always gently mocked her obsessions, joking that she likes dogs more than people, but she says she doesn't care.

"I say I get 'proody' instead of 'broody,' because if I see a puppy I'll just sit on the floor and let it climb all over me," she said. "I just think dogs are less demanding, they're so much fun, they're so affectionate, and they mostly don't have tantrums."

Before her Cavalier King Charles spaniel, Paddy, died in May, Kellard's life revolved around him. When she suffered from anxiety and depression, he was the only thing that got her out of bed some days. In his later years, Paddy lived in her spare room, where he slept on a double bed. Kellard and her husband even stopped going on vacations abroad because Kellard didn't want to leave Paddy at home alone. Instead, they'd go to dog-friendly cottages within the country.

"Even at home, we got to a point where we didn't leave him home alone," Kellard says. "So if we were eating out, we'd go somewhere dog-friendly and would always order him a doggy sausage or share some of our meal with him.

"It's a real adjustment finding my new sense of purpose now my life isn't revolving around Paddy," she adds. By the end of Paddy's life, Kellard says, she was spending an average of £200, or about $260, a month on him — sometimes up to £400.

Across the board, more pet owners are splurging on their animals. In its annual surveys, the American Pet Products Association has found that pet owners have reported spending more on things like treats, food, toys, and clothing each year. In response, a host of boutique pet stores have popped up. In 2022, San Francisco welcomed Dogue, a "pawtisserie" serving minimally processed artisan treats like pastries and "dogguccinos." New York City is home to spots like District Dog, which makes pup-friendly birthday cakes, and Love Thy Beast, which sells custom dog apparel. Luxury pet hotels such as Chateau Poochie in Pompano Beach, Florida, cater to dogs and cats with high-end boarding services: Cats can relax in "three-tier deluxe condos" with virtual coral reefs and private powder rooms, while dogs enjoy gourmet meals, spa treatments, and round-the-clock care.

Despite how much effort Kellard put into taking care of Paddy, she says she still prefers pets over children because they require much less responsibility. "You can go on holiday for a week and leave your dog with a friend or family member. You can go out for a nice meal and leave the dog at home," she says. "I generally just find dogs a lot more relaxing than children. Children seem to need a lot more attention than dogs do."

While some millennial dog owners are forgoing having children, others are using dogs as training for parenthood.

Michael Wang, who lives in New York City with his wife, Adriene Wong, describes their corgi, Dash, as their "starter kid." For years while the couple, who are in their late 30s, were dating, Wang protested Wong's desire to get a dog. "I was scared of commitment and scared of responsibility," he said. But on the way back from their honeymoon in December 2018, Wong revealed that they'd be getting a dog in a month. "What are you going to do? Divorce me?" she asked him.

When Wang saw Dash in January 2019, his heart melted. He says he realized he'd been focusing on the negatives, such as the extra cost and responsibility, while forgetting about the "extra joy" a dog would bring into their lives. They decided to get their second dog, Lili, last November, a few months before their baby was due.

The couple say they learn things from their dogs "all the time" and have been able to apply some of these lessons to parenthood. Wong says Dash and Lili have taught them patience in particular. But she says that "there's a lot more that goes into raising a human being than a dog, for sure."

For some, approaching dog ownership as a trial run for parenthood may be more harmful than helpful for the dogs, given that the skills required to raise them are drastically different.

"We are not their parents, they are wholly different species from humans, and there is a total language barrier," says Mark Van Wye, the CEO of Zoom Room, a chain of indoor dog-training gyms in the US. Treating a dog as a "fur baby" and failing to create boundaries, he tells me, can lead to them thinking they're entitled to things such as toys, food, or even a space on their owner's lap. "This can lead to aggressive behavior, especially if they feel their 'rights' are being threatened," he says. "It's like giving a kid all the candy they want and then wondering why they're bouncing off the walls."

Dogs who are treated as children could also become stressed — or at least their owners are increasingly concerned about them being stressed. The American Pet Products Association found this year that the use of calming products, such as anxiety supplements, diffusers, and chews, had grown by 168% for dogs and by 174% for cats since 2018. Van Wye says that dogs that are constantly doted on or "treated like they're fragile" often struggle with anxiety when they're left at home. "They've grown so accustomed to being the center of attention that they don't know how to cope when that attention isn't there," he says, adding that this can lead to destructive behaviors like excessive barking and chewing up furniture.

Dogs' physical health is also a growing concern. A 2022 survey from the Association for Pet Obesity Prevention found that 59% of dogs were considered overweight or obese, a 3-point increase from 2018. Sean Prichard, the head canine fitness coach at Pant & Wag, a dog fitness company, says he has noticed more people coming to him with obese dogs. He says he believes the issue stems from owners feeding their dogs as if they were children rather than sticking to proper canine nutrition. "Instead of feeding the dog on a set schedule with a set amount, I have several clients who feed their dog whenever the dog 'asks' for food, and this includes giving the dog bites of human food," he says.

Dog owners can't be blamed entirely for the changing behavior. Dr. Eliza O'Callaghan, a managing veterinarian for Small Door Vet's New York City locations, told me that the pandemic had "definitely left its mark on dog behavior." She's seen the biggest shift in young dogs that spent the first couple of years of their lives constantly surrounded by their owners. "Now, as people return to the office, many of these dogs are struggling with significant separation anxiety," she says.

Wong says she and Wang are "very guilty" of treating their dogs as babies. "We tuck them into bed," she says. She says that when they got Dash, she wanted him to have the "best diet," so she looked up recipes to make for him at home and bought organic ingredients and expensive chicken from Whole Foods. Wong recalled one day when Wang came home, saw her cooking, and asked what was for dinner. "I looked at him and was like, 'Well, this is for Dash,'" she says.

Eventually, she realized it was too much and started buying dog food.

"We love them. We want what's best for them," Wang says. "Do we go overboard? Yeah, maybe sometimes. And then we'll reel it back."

When I ask Kim whether she thinks she's ever gone overboard pampering Bodhi, she says the thought had never occurred to her. "I know there are people that are critical of dog parents who do 'too much' for their dog," she says. "I would urge them to take this energy and direct it towards dog parents that do too little and neglect or abuse their dogs instead."

Pouring energy into pets provides a sense of companionship and purpose that has traditionally been fulfilled by children — while avoiding the lifelong financial and emotional commitment kids require. But just like with children, it's possible to go too far. And no one wants to raise a spoiled brat, human or animal.

Aimee Pearcy is a freelance journalist who writes about technology and digital culture.