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AIBU?

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Original poster

AIBU to expect my boyfriend to know the difference between step and half siblings

115 replies

Lauralaaaa · 17/09/2026 21:44

AIBU for thinking my 30 year old boyfriend should know the difference between a step brother and a half brother?

OP posts:
AshCullen1894 · 18/09/2026 16:55

Yes, but it's not uncommon for folks not to know, especially if they have not blended families.

Everleigh13 · 18/09/2026 16:58

I reckon quite a few people wouldn’t know.

Brummyhelpplease · 18/09/2026 18:12

The smarter technology gets the dumber the human population seems to be getting. I cannot fathom how you would not know the difference at all.

Shinyhappyapple · 18/09/2026 18:28

Depends on if it’s come up in his or in his friends’ families really. I’m not sure that my husband is clear on this TBH.

AutumnLoverButNotYet · 18/09/2026 18:31

HoraceCope · 17/09/2026 22:17

I call my half sisters, same father step sisters, not a big deal to me

That's like calling your feet your hands.

There's nothing stopping you doing it it's just incorrect.

WhatNoRaisins · 18/09/2026 19:13

I think if you know you're using the wrong term you have to accept that there's the potential for a lot of confusion.

fumingrightnow1 · 18/09/2026 19:16

I don't see the big deal most people don't know a few things that are quite basic. Don't you ever hear something and think omg how did I not know that

Morepositivemum · 18/09/2026 19:19

I’d have to think about it to explain it if I had to!!

Halfandhalf26 · 18/09/2026 19:20

I thought half siblings were same mum different dad. And that step siblings were different mum same dad.

Bananacrepewithnuts · 18/09/2026 19:21

If he is from a family that has no steps and halves then it is reasonable for him to not understand those terms.

Chill out.
X

TwoLeftSocksWithHoles · 18/09/2026 19:25

Half sibling vs Step sibling... scoff

Yes, on that the basis alone, you should LTB and if this leads to financial hardship then you just 'take in ironing'.

Bjorkdidit · 18/09/2026 19:25

Halfandhalf26 · 18/09/2026 19:20

I thought half siblings were same mum different dad. And that step siblings were different mum same dad.

Well I was going to say it was pretty obvious what a half sibling was and step siblings are the other kind, but then we get posts like this.......

Halfandhalf26 · 18/09/2026 19:45

Bjorkdidit · 18/09/2026 19:25

Well I was going to say it was pretty obvious what a half sibling was and step siblings are the other kind, but then we get posts like this.......

Show quote history

🙄 things are obvious to some people not others. This is what I was told as a child. I never questioned it. And its never been a subject in my life. Until this thread . I'm sure there's probably things you don't know that are obvious to others

Waitingfordoggo · 18/09/2026 19:49

Exactly this.

Edit: sorry, meant to quote those saying they haven’t needed to use either term very often so need to engage brain first.

Waitingfordoggo · 18/09/2026 19:50

Edit: duplicate post

EmeraldShamrock000 · 18/09/2026 19:50

It is not unusual. Blended families often have step children and half sibling children in the mix. It all blends together, it can be confusing if it isn’t your experience.

beaglescurleduplikebagels · 18/09/2026 19:54

Brummyhelpplease · 18/09/2026 18:12

The smarter technology gets the dumber the human population seems to be getting. I cannot fathom how you would not know the difference at all.

Because lots of us have precisely zero experience of that kind of relationship, so while we may technically know the difference, they're not terms we know intuitively.

My dad has both step and half siblings - I've never met half of them and have to really think when I'm talking about (say) Jane as to whether she's his step sister or his half sister.

HoraceCope · 18/09/2026 19:55

AutumnLoverButNotYet · 18/09/2026 18:31

That's like calling your feet your hands.

There's nothing stopping you doing it it's just incorrect.

Show quote history

i am rarely talking about them , no body else cares at all, so i will carry on

TattieSconeEggAndBacon · 18/09/2026 19:59

I agree, having both step and half siblings. it grinds my gears a bit when people who know our family well call my half brother (who is just my brother) my stepbrother because it feels diminishing. I think if you don’t have a blended family some people just genuinely don’t think about the difference.

Pllystyrene · 18/09/2026 20:00

My husband is very intelligent and will often talk about things I can't understand at all but also spent most of his life thinking ponies were just baby horses 🤷😂

Brummyhelpplease · 18/09/2026 21:08

beaglescurleduplikebagels · 18/09/2026 19:54

Because lots of us have precisely zero experience of that kind of relationship, so while we may technically know the difference, they're not terms we know intuitively.

My dad has both step and half siblings - I've never met half of them and have to really think when I'm talking about (say) Jane as to whether she's his step sister or his half sister.

Show quote history

You don't need to have a blended family to know that children with both the same parents are full siblings, ones that share one parent and not the other are half siblings and people two adults who have kids separately and not together when they get married/move in together makes their kids step siblings.

LydiaJayne · 18/09/2026 21:14

Brummyhelpplease · 18/09/2026 18:12

The smarter technology gets the dumber the human population seems to be getting. I cannot fathom how you would not know the difference at all.

If it's not a feature in your live or anyone you are close too I can totally see why people wouldnt know
No one knows everything and not like it's a universal relationship that we all have or even a regular topic of conversation

I have a 30 year old nephew and Im not sure he'd know tbh, doesnt mean he's dumb

I can't fathom that you can't fathom it 😁

deadbobaplace · 18/09/2026 22:03

Halfandhalf26 · 18/09/2026 19:20

I thought half siblings were same mum different dad. And that step siblings were different mum same dad.

I am so sorry somebody thought it would be funny to tell you that and have you grow up believing it.

Did you really not figure it out until this thread?

Tryagain26 · 18/09/2026 22:06

Everyone should know the difference but a surprising number of people don't.

Shatteredallthetimelately · 18/09/2026 22:09

There are many on here that don't even understand their own DP's kids aren’t their step children unless they're actually married to said partner, so yes, it's understandable that your boyfriend may not know the difference.