I don't care

Well we don’t actually know what the kids said, the OP has only posted twice and hasn’t given much detail. She says ‘they told me they were bisexual’, but I doubt the messages just said ‘hi mum, I’m bisexual’.
Regardless, sexual orientation is very rarely just about sex.

It was a big deal for her to tell you. You were dismissive of that.

No

Hetero is the default so it’s not the same. Are you saying if they texted you something personal you would respond by saying you’re not interested? “Mum, I’ve met someone I really like”
“Who cares, I’m not interested in your love life”?

What a strange thread. What outcome were you looking for OP?

Of course you should care about your kids but it doesn’t matter what their sexual orientation is.

When my sister told me she bi I said "Oh OK!". She then didn't speak to me for 6 months as apparently I had been dismissive of her big reveal when actually I didn't think it was a big deal.

Where about do you live? Is the area MC? This isn't happening across the country, at least not with the boys, here in the NW, largely WC areas.
Not that being gay wouldn't be accepted, but it's usually announced once the young person is having a proper relationship, over 18, just in case there is any backlash.
@Thepeopleversuswork what did your sibling want from your Dad? A parent could go the other way and start to have worries and fears, from STDs to never being able to have children.

But the op’s kids didn’t speak about relationships they were having. If they had then the op could have had an interest.

For all those who say that it’s not just about a sex life, well then the op’s kids should have said what else was on their mind. Otherwise it IS just about their sex life

I don’t understand all of this ‘coming out’ business.

I’m bisexual and never came out, i just introduced my then girlfriend to people.

my eldest did the same pretty much. He told me that he was going on a date and when I asked about ‘her’ he just said “his name is Peter, he works with me” and I told him to have a great time, exactly the same as always.

Did your sibling invite his father to speak about his sex life or is this a one direction only conversation?

It’s not just about sex.

I actually do! And if it’s important to her, I’ll listen.
Anyway, my point was that people are reducing it down to just sex. ‘I don’t want to hear about their sex lives’. Fair enough, but being bisexual isn’t just about having sex with men and women. It’s about relationships. I’d never tell my kids that I don’t care about their relationships.

if they say anymore you could answer by asking them if they would like you to tell them about your specific sexual preferences

Two of mine are gay. When they told me I replied that I knew already and it it was cool. As long as they were happpy that's all I was concerned with they are still the same people they were before they told me.

But what do you want to be treat the same way as everyone else or to be given a medal nobody gives a shit its 2026.

Then say about a new person you've met or fancy. If you don't need to announce your straight you don't need to announce your bi or gay

You don't have an oversharer do you.

There have been a lot of AIBU threads recently that are dismissive of gay people, anti-Pride, why don't they keep it to themselves, straight people don't need to come out etc etc. Quelle surprise that a lot of those piggyback on this site's pre-existing transphobia to get some good old-fashioned homophobia in there too.

Have they really

Yeah don’t say this to a gay or bisexual child and then expect them to remain in your life.

The children obviously didn’t think so, which is why they went out of their way to tell their mum. I just can’t imagine my kids thinking something is important enough for them to want to go out of their way to tell me about it specifically, and my reaction being ‘I don’t care’. If they care then I care.

Just be glad it was old fashioned Bi-sexual, not one of the other 452 Genders and Sexualities that Gen Z has made up for attention seeking purposes

I really hoped that these “I don’t care what they get up to in the bedroom as long they keep it to themselves” attitudes were dying out. Your sexual orientation is not just about your sex life fgs.

Its all good and well to say you “don’t care about their sex life” but its not only about their sex life.

Its about who they choose to spend their time with
Its about how they are seen by society
Its about them feeling socially safe versus having to pretend all the time
It could impact a decision about having children and a family

I’d be careful with the “I don’t care” approach. I have a gay sibling and our father very much took the “I dont care” approach. He wasn’t homophobic but made it clear he didn’t want to spend time thinking or talking about it. It left my sibling feeling very resentful.

Lack of judgment = good
Lack of care/interest = not so good

But surely this is my new boyfriend/girlfriend or I've met this guy/gir i really like is enough rather then announcing your bisexual