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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:
Waitingfordoggo · 18/09/2026 19:50

Edit: duplicate post

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.

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

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.......

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'.

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

Halfandhalf26 · 18/09/2026 19:20

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

Morepositivemum · 18/09/2026 19:19

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

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

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.

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.

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.

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.

Everleigh13 · 18/09/2026 16:58

I reckon quite a few people wouldn’t know.

AshCullen1894 · 18/09/2026 16:55

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

WearyAuldWumman · 18/09/2026 16:54

You're not unreasonable, but I've come across so many people who don't seem to know the difference.

When I was working, I had pupils who referred to their 'stepsisters', when - in fact - all the siblings had the same father. The children used the term 'stepsisters' because that's what they'd heard their parents saying.

weavingrugs · 18/09/2026 16:51

@Lauralaaaa
I think, as he says, he probably does know, but if he doesn’t have reason to use the terminology much it won’t come as naturally to him as someone who does.

beaglescurleduplikebagels · 18/09/2026 16:47

It's one of those things I know, but often have to think about as they're just not terms I use on any kind of regular basis.

WhatNoRaisins · 18/09/2026 16:46

A lot of people these days seem confused by the terms so it doesn't suprise me too much.

gannett · 18/09/2026 16:46

Seems like a basic thing to know but if you don't grow up with either I can see why you'd just not think about it that much.

I would have to look up what once, twice removed means in relation to cousins. I did know once but obviously didn't care enough to commit it to memory.

FFSItsTooHot · 18/09/2026 16:45

You'd be surprised at the number of people who don't know the difference! I have friend who has a half sister, same mum, different dad. But she will keep calling her her step sister!

Passementerie · 18/09/2026 16:44

BigWig78 · 17/09/2026 23:03

I’d expect someone to know the difference but I wouldn’t expect them to differentiate. My kids all call each other siblings and I’d be upset and annoyed if they said “half” about each other even though the older two are from my first marriage. They’re brothers and sisters as they’re all my children and that’s how they think of each other too.

Respectfully, how they think of one another, or what they call one another, is up to them, surely? Obviously they're all your children, but that doesn't mean they necessarily think of one another as full siblings, given that they have one different parent they'd have to mentally delete to do so.

OriginalSkang · 18/09/2026 16:42

My half sister is just my sister. I've occasionally had people think she is my step sister out of stupidness

Original poster
Lauralaaaa · 18/09/2026 16:40

Thanks everyone! That’s very helpful, he’s usually intelligent and is now adamant he does know just not off by heart 😂

OP posts:
BigWig78 · 17/09/2026 23:03

I’d expect someone to know the difference but I wouldn’t expect them to differentiate. My kids all call each other siblings and I’d be upset and annoyed if they said “half” about each other even though the older two are from my first marriage. They’re brothers and sisters as they’re all my children and that’s how they think of each other too.