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

No, but you know now that it’s wrong.

lol . Yep .

I think if you don’t have step or half siblings it could be an easy mistake to make if you’re not familiar. But it’d be a cold day in hell before I referred to my brother as my half brother, even if he technically is!

They won't be common in some families. No one in my (huge) extended family either side has step or half siblings, and there's just one one group of half-siblings in DP's huge extended family. I'd probably have to think for a moment if introduced to someone's half or step sibling. And I'm quite intelligent as far as I know ;)

Some people are just a bit thick or else incurious and don’t care to know things.

Absolutely this. Bowls, football, Motorsport, naming of parts of other people's families. Not remotely curious.

Much more interested in aunt Agatha's shenanigans, whether she's a friend of auntie Mary's, an actual biological aunt or a random really 3x removed. People interest me and individuals I care about. Labeling the relationships between them not so much.

Knowing that the word half sibling means someone is half a sibling aka one shared parent isn’t details. It’s basic knowledge of both human relationships and words. Half Sibling is a half sibling it’s hardly rocket science. Step is slightly trickier but childhood stories have enough stepmothers that you’d think knowing it meant by marriage was picked up by anyone who ever watched or read Cinderella.

If you can’t pick up and remember those two words you are, I’m afraid, possibly thick or, as I said, incredibly incurious.

Don't people read?

I can see why people who don’t have any experience of blended families don’t get it immediately, but then I always refer to my half brother only as my brother (and DH’s half-sister is just his kid Sister) so I suppose we don’t help matters.

Yeah. 3 masters degrees would confirm I'm thick.
Like I said, I can get there if I think about it. Like I can name several kinds of dinosaur if I think about it. And even chemical formulae . It just isn't something that comes up in my day to day life and step siblings occur in my reality as often as t-rexes.
I read widely but I'm more interested in people and personalities than the naming if the relationship between them.
I think you might just have to accept that other people have different experiences from you, and that's ok.

I don't have much experience of step or half siblings but it doesn't mean I don't understand what the terms mean, it's not hard.

Do people not know how babies are made?

I agree that we can't know everything, but it's the almost celebratory attitude of not knowing something and deeming it not important enough because it doesn't affect me that's so bothersome .

You could literally date, marry and have children with a step sibling and if you didn't know the difference between step and half , this could be a very big deal and cause people to think you were some kind of weirdo perv😄.

It's meant as explanation rather than celebration. Which is reasonable when the question at the outset is how could someone not be particularly familiar with the difference.

I'm not so sure - some of these replies are reading like how would a normal person possibly know this - instead of wow that's quite a big distinction, I didn't realise .
Imagine someone on here saying they have no idea who the prime minister is or which continent the UK is in and then everyone else piling on to agree that well it's not that important, we can't know everything - that's how I'm interpreting replies.

I'm not trying to shame anymore, please believe that, but I also don't want ignorance to become acceptable - I'm embarrassed when I don't know something really obvious.

anyone**
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