Technically, if you share only one parent, you’re half siblings. But many siblings who fit the bill find the phrase insulting. They don’t use it in their families, but other people ― those who can’t seem to comprehend that family is much more than 100% shared biology ― bring up the distinction often.
“I remember learning about the term in school and going home and asking my mom if my sister and I were half siblings, and she was not pleased,” said Carla Zuill the editor and founder of an online magazine who lives in Manchester, England. “She told us that we were not halves as we were both birthed by her.”
Now a parent herself who has children with different dads, Zuill stands by the idea that if you have the same mom or dad, you’re siblings. Period.
“My three kids are simply my children and each other’s’ siblings,” the mom said.
“They have very distinct personalities, and I love it; it makes their sibling dynamic very interesting,” she said. “The boys are super close, my oldest and youngest are always bickering, but my daughter and older son are extremely close.”
But Zuill said one thing is clear: “Do not try to mess with any of them because the other two will not stand for it.”
“Half but wholly sibling” experiences like this are incredibly common. According to a 2020 census report, 1 in 6 children younger than 18 lives with a half sibling. It’s more common for children living with a single mom to have at least one half sibling present (32.5%), the researchers found. Only 7.6% of children living with a single dad had at least one half sibling. Among children living with two parents, 12.8% had one half sibling or more living with them.
While half siblings and blended families are common now in the U.S., most academic research on family dynamics still tends to focus on siblings of the “full” variety, according to Geoffrey Greif, a professor at the University of Maryland School of Social Work and co-author of “Adult Sibling Relationships.”
“Half siblings have been the stepchild ― joke intended ― of sibs research because they are a more complicated topic to pursue in an already complicated topic,” he told HuffPost.
When you’re studying siblings, you have to account for gender, birth order, number of siblings and age gap, he said. When you add half siblings to the mix, it gets all the more complicated.
“You may have folks who live together, who have never lived together, people who just met each other or are born years apart,” Greif said. “It’s a complex picture, sometimes with few commonalities.”
Indeed, it’s true that for some half siblings, the “half” part of the equation is very much felt; maybe their divorced parents didn’t encourage integrated lives, or the siblings didn’t know the other existed until much later in life.
“Generally, what determines how close half siblings are going to be is proximity,” Greif said.
Michael E. Woolley, also a professor at the University of Maryland School of Social Work and co-author of “Adult Sibling Relationships,” thinks that there’s something special about how bonds between half siblings are forged.
He told HuffPost the kind of relationships that develop over time with half siblings has more to do with who they develop to be as individuals rather than what their parents want, how long it took for them to meet or even whether they shared a bedroom growing up.
“Full siblings who live together all through their childhood can have conflictual relationships and conflict that lasts into adulthood,” he said. “Half siblings can form strong bonds that last a lifetime whether they live together growing up or just see each other during ‘visits,’ such as holidays and summer.”
When half siblings choose to see each other as “full” family, it’s a true buy-in, a show of love and real kinship beyond anything the same two parents could encourage.
Woolley knows this firsthand: “I have two full siblings and three half siblings, and I am closest to one of my half brothers, who is much younger than I am.”
Both he and Greif hope there’s more research on this type of sibling dynamic. Until then, though, we decided to ask people who are technically “half” siblings what it was like growing up and how they feel about the divisive term.
Responses have been lightly edited for clarity and length.
‘It never even crossed my mind that my littlest sisters were anything less or other than siblings.’
“I’m the oldest brother of six. The two youngest are my half sisters, Kacie and Ali. I’m in my late 40s and they are in their late 30s, and they still call once in a while to lean on their big brother for support. It seems weird to refer to them that way, but they do have a different dad. It never even crossed my mind that my littlest sisters, or, as we used to call them, ‘the little girls,’ were anything less or other than siblings.
“We grew up in the Pacific Northwest in the Cascades east of Tacoma in a little town called Bonney Lake. We played in the woods a lot and ate berries, and we walked to the store for candy together, we made forts and played war. We are still strong as a group and rely on each other. I was 24 when our mother died of cancer, and my littlest sisters were 13 and 14. They lived with our aunt and uncle until they moved out on their own. I had moved away after our mother passed, but I’d come pick them up and have them stay with me for spring break and Christmas break and summer. We all grew up as Jehovah’s Witnesses. I got out of that religion as soon as I turned 18, but both of the little girls are still practicing. That difference alone should be a huge gap in our status as siblings, but it isn’t.
“No job title on earth compares to the simultaneous cruelty, honesty and protectiveness as the title of ‘big brother.’ They call on me because they know they will receive the truth and as honest guidance as they can find anywhere. They know that I know their full potential and that I don’t even question their ability to live up to it. I even express a brotherhood between myself and their husbands. They include me and I include them as though we had known each other our whole lives. I’ve seen how safe and sound my little sisters are with them. That makes them brothers.
“I know how lucky I am to have spent my childhood playing in the woods and eating berries with my siblings. That’s where I was able to watch them and see for myself how powerful and amazing they are.” ― Josh, 49, who lives in Pendleton, Oregon
‘I never considered her anything other than my sister.’
“I have three siblings on my father’s side that I am aware of, and with my mother, just one who I consider my sister. I am the youngest out of the two of us. We grew up in the same household. My mother had her when she was a senior in high school, and I came seven years after that.
“My older sister is seven years older than me; she was born premature and was smaller than most small children at that age. Our mother would dress us alike, and people would think that we were twins by the time I was 3 years old. While we were similar in build for a good part of our lives, there was a huge age gap between us.
“We are very different people personality-wise, and I feel like she wanted to distance herself from being associated with me. In turn that created an even larger gap in our relationship. I oftentimes felt left out when she would go do things with her father. When I was 10 years old, she graduated from high school and moved away, so I spent the rest of my formative years alone. For a major chunk of my life, I felt like an only child.
“I do remember being in the third grade and a kid on the bus tried to explain to me how my sister wasn’t really my sister because we had different dads. But because we both lived with my mother full time, I never considered her anything other than my sister. We definitely grew apart as we got older, because we were physically apart once she became an adult. I am now 23, and this is the first time it feels like we are actually building a relationship outside of being siblings. I know a lot of kids that come from same-parent households, they didn’t get along half as well as my sister and I do. I love my sister, and I wouldn’t change anything about her.” ― Da’Janea Holmes, 23, who lives in Dallas
‘Our sister is our sister. Full stop, and woe to the person who claims otherwise.’
“I have two siblings, both younger. I am the oldest. My brother, Chris, is fully biologically related. Sabrina, our sister, is our sister. Full stop, and woe to the person who claims otherwise. I’m absolutely the protector of us kids. We grew up in an Air Force family. There was a very, very tumultuous time of the divorce and subsequent remarriage.
“Today, Sabrina’s own family is quite similar to ours growing up, in terms of makeup: She has two kids with her first husband and two more with her current husband.
“She is remarried to an absolute gem of a man, but the first husband is a total piece of work. He slapped my sister once. I was there in under 10 minutes after I was told. The way I see it, she is my sister, those are my nieces and nephews, and I would kick in the gates of hell for them.
“As far as viewing her as a half sibling? Not a chance. My brother, Chris, or I would come in like a one-man army if she was in danger.” ― Robert, 44
‘My sister didn’t even flinch at the idea of raising me.’
“I have three siblings. One brother that is fully related, and the other two, a boy and a girl, are my half siblings. I consider them all siblings because we all share the same mom. My mom made sure we didn’t see each other as anything less than full siblings, as it shouldn’t matter.
“My older brother and I grew up together until I was 13. When my sister was 27, she adopted me. My parents gave her parental rights when they found out I’m gay. My sister didn’t even flinch at the idea of raising me. I’d be nothing without her in my life. It was weird growing up in my teen years with her as my guardian. It was like I had a mom and a sister, which made fights really weird. But as I grew up, our relationship only grew stronger. Given our age difference, though, people often think she’s my mom. I don’t really bother correcting them. What’s the point in that? She has a daughter now that’s 3, and even though she’s my niece, it’s like she’s my sister in a way. It’s odd, but I wouldn’t trade it for anything.
“To show how close my sister and I are, here’s a story: I was fired from a job once. My mental health was just in the garbage and on fire. My sister pulled out all the stops to help me: Lending me money for rent, calling or texting every day, just making sure I felt loved. My ‘half’ sister loves me more than my real parents ever did.
“I’m not surprised that people think of half siblings as nothing more than a sort of ‘guest’ in the family. But I roll my eyes at that. My ‘half’ sister is amazing.” ― David, who lives outside of Boston