What If Your Ideal Roommate Is... Your Sibling?

“That’s so cool,” people say when I tell them that I live with my younger sister. Then, almost always: “My sibling and I could never do that.”

In 2021, at the tail end of a relationship in which my partner and I lived out West, I returned to New York and began apartment-hunting with my sister. The two-bedroom we found in Park Slope, Brooklyn, felt fantastical: spacious, recently renovated, and suspiciously affordable, with copious light and bedrooms as far apart as architecturally possible.

We later learned that our landlord, after whittling a massive pile of applications down to two, asked the upstairs tenant if she’d rather share the building with sisters or a couple. Our neighbor, who has a fraternal twin sister, chose us.

“The nice thing about siblings is you know each other really well,” says generational expert Lynne Lancaster. “You know where they’re going to bug you and where you guys get along.” With roommates and friends, you’re more likely to tiptoe. “But [with] siblings, you can just say, ‘You are such a pig. Would you please pick up your dishes?’”

During the first year my sister and I co-habitated, our fights were infrequent but devastating. A debate over emptying the dishwasher would culminate in a blowout over an incident that occurred during toddlerdom. After one particularly catastrophic argument, I dragged myself to a party, face so swollen from crying that an attorney friend inquired if I’d endured some sort of botched facial injection and required legal support.

The landscape of what it means to “grow up” and make a home is changing.

Still, after two and a half years, we have grown strikingly closer and more synchronized. This success made me wonder if there were others like us. According to a 2024 report from CoBuy, a co-buying and co-owning platform, 39% of co-ownership arrangements include relatives. Pam Hughes, CoBuy’s cofounder and COO, estimates that number is growing, both due to necessity and because many people — particularly millennials — are delaying or choosing to forgo milestones like marriage and children.

As of 2017, there were nearly 79 million adults in the United States living in a “shared household” — i.e., one including an “extra adult,” like a friend, adult sibling, or roommate. This number has risen by more than 20 million since it was first measured in 1995. It’s clear that the landscape of what it means to “grow up” and make a home is changing.

So, who were these other people weary of living with near strangers, who simply wanted to co-habitate with someone who shares roughly 50% of the same DNA and doesn’t care if you pee with the door open? I decided to find them.

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In 2018, Blair was living in a “unicorn apartment” in Brooklyn Heights: a shockingly underpriced two-bedroom on a tree-lined street. When her best friend moved out, she and her younger brother, Kip, went out for wood-fired pizza and had a “very adult conversation” about what it might look like to co-habitate.

It wasn’t the most far-fetched idea; as kids, they’d shared bunk beds for years. Both single, they made one “hard and fast” ground rule. “Neither of us [could] bring anybody home to hook up… if the other person [was] home,” says Blair, now 32. “We literally shared a wall.”

Kip — newly graduated, partying a lot, bartending, and studying for the LSAT — says that it was nice to have an excuse not to bring nascent romantic interests back to his apartment. Now 29, he characterizes that period as a “pretty crazy time” in his life. “It was really comforting to know that [I was living with] a person who was reliable and who I enjoyed spending time with.”

“It [felt] really, really natural for us to just be sitting on the couch, stone-cold sober, dying laughing, because that’s what our growing up time was like,” says Blair. Their favorite bit involved Blair voicing an elderly, genderless character who would complain in a crotchety Brooklyn accent that they couldn’t find their nightguard. Kip, meanwhile, would physicalize the character with hand gestures. This kind of playfulness can feel more organic between siblings than later-in-life friendships.

“It doesn’t translate that well,” says Blair, “but it really makes us laugh.”

Besides one incident in which Kip accidentally hit Blair in her shin with his new skateboard, neither of them harbor negative memories from co-habitating. “You went from a sibling I felt very close with,” he tells his sister, “to one of my best friends.”

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In 2020, when Barb and her younger sister were both newly single, the 30-somethings moved into an apartment in Bloomfield, New Jersey, along with Raven’s then-toddler son, Nuggie. They expected the arrangement to last for a year or two.

Four years later, Barb has become a parental figure to Nuggie. “I couldn’t do it without her,” says Raven. “She knows his routine like I know his routine. It’s like having another mom in the house… She spoils him rotten.”

When Barb was diagnosed with breast cancer in 2022, Raven says, “It was like, no question, I’m on deck. She’s going to be my No. 1 priority.”

To save money, the trio relocated to Barb and Raven’s childhood home in Newark, a big blue house framed by two hibiscus trees named Jolene and Jasper. “It’s hard to watch a sibling go through something [like that],” says Raven. “She was crying. I would come up and [say], ‘It’ll be OK.’ And then I’d go downstairs and I’d cry, and then come upstairs and [say], ‘What can I do for you now?’”

That support was crucial. “She was the one who changed my drains, helped me bathe, and fed me and encouraged me and took care of me,” Barb says. Without Raven’s help, Barb says, “I don’t know what I would’ve looked like on the other side of that journey.”

This kind of familial caretaking isn’t always a given in the United States. “What we’ve learned from the pandemic is [the importance of] interdependence,” says Lancaster. “I think community is good for human beings.”

Barb is currently cancer-free and gearing up for one final surgery. “How are we going to celebrate your triumph afterwards?” muses Raven. They’ve been discussing travel. “Every plan is … you and me, you and me. I’m so happy about it.”

“It’s kind of like a halfway house between living with your parents and being on your own,” an acquaintance once commented, as if there is some portal to adulthood more daunting than being asked, daily and prior to morning caffeination, to confront the deeply entrenched childhood patterns that most only face annually at holidays and family reunions.

When I tell people that I live with my sister — and I do, constantly, in a nearly confessional manner that maddens her — some react as if I’m admitting that I am fundamentally unable to care for myself.

“It’s kind of like a halfway house between living with your parents and being on your own,” an acquaintance once commented, as if there is some portal to adulthood more daunting than being asked, daily and prior to morning caffeination, to confront the deeply entrenched childhood patterns that most only face annually at holidays and family reunions.

Mothering — specifically, my inability to stop doing it — has been my sister’s and my largest obstacle. It was also a challenge for Jabrea when she left Iowa nearly three years ago and moved into a two-bedroom in Brooklyn’s Prospect Lefferts Gardens with her older sister, MaKayla. At first, she constantly tried to “reel back the sort of older sister/younger sister dynamic,” she says. “I’m like, ‘Girl, we’re both adults… I’ll clean my dishes, don’t worry. I got it.’”

With time and discussions, the pattern abated. Their birth order is now most apparent in the way they each spend money, with MaKayla, 30, often trying to persuade Jabrea, 25, to purchase sleek investment pieces for their apartment. Jabrea often pushes back, gravitating toward lower-budget items that embody “more of a cluttery, knickknack sort of style.”

This aesthetic tension resonates with me; one early squabble with my sister occurred when she brought home a bunch of decorative gourds. “Look what I got for us!” she announced, as if there was ever a day in my life that I felt something missing from my living space and it was a heap of fleshy, bumpy, nonfunctional fruits.

Like us, the Iowa natives have gone from close to closer. While MaKayla has set boundaries around caring for Jabrea’s cat, Monday — namely, she won’t — she does like to pet her. MaKayla is an opera singer, and unlike hypothetical roommates who might be less invested in her career, Jabrea doesn’t mind listening to her practice. “I work from home, and so sometimes I get calls and I’ll have to be like, ‘I’m on this meeting; you can’t sing.’ But otherwise I don’t care,” she says. “She could sing anytime.”

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Many siblings I spoke to characterized their co-living situation as temporary, a liminal stage between the intrusion of roommates and the ultimate goal of creating their own nuclear family.

Lancaster, a widowed baby boomer, spent eight months living with her younger sister after her sister’s husband passed. “It was a safe [and comfortable] place to go through a loss and relaunch into the next phase of her life,” says Lancaster, now 64. It had been 45 years since they last lived together.

The Villalobos Brothers, now a Grammy Award-winning band, spent 13 years co-habitating in a dilapidated Victorian-cum-artists’ colony in The Bronx’s Marble Hill. After the three siblings studied at separate universities, reuniting under one roof allowed them to rediscover each other as adult musicians. “That’s how we started developing our sound as a band,” recounts Beto Villalobos, 41. “It was really priceless.”

For others, the trajectory is less clear. “Just how long do you think this will go on for?” my sister asked, rudely, not long ago when I expressed reticence about her accepting a job that would require her to relocate. (She turned it down a few days later.)

“I don’t know,” I lied. In truth, I was thinking about Ann Napolitano’s novel Hello Beautiful, in which two of the four sister-protagonists live in a “super-duplex,” side-by-side houses large enough to hold partners, children, pets, and stray loved ones, with an interhouse speaker system to boot.

This whimsical setup is not just the stuff of fiction. Barb and Raven’s brother, who lives one town over, recently mentioned that he and his partner are considering joining them in their family home.

“It’s going to be a house full of madness,” says Raven. “But I’m here for it.”