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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

15 year-old know it all son

308 replies

Spiritedlight · 24/02/2026 10:00

Hi everyone

I would like to have thoughts on how to handle/progress with son. He's 15, smart, lovely, very opinionated, completely resistant to being told anything and thinks he knows it all.

For example, a discussion about astrology/space etc - whilst DH is very knowledgable, DS will disagree with everything DH says, and quote, frankly, bollocks a lot of the time.

If we talk to him about the school's recommendations for self-study in Year 10 - which I know he's not doing, because I know what they expect - e.g., 2 x 30 mins of going over triple science lessons a week -he will completely tractor over the discussion with comments like, "I'm doing it through homework, it's about quality not quantity (he does the bare minimum), my grades are very good (not as good as he thinks) etc etc". Everything gets brushed off, diminished, he knows best. Always.

It's the oddest, most annoying thing. I've tried to talk to him about it but I don't get anywhere - except that he thinks we are telling him off, which suggests to me this is a defence mechanism. And we are really not telling him off in those moments, we're trying to open up conversation and be supportive about these school years.

I'm worried about his grades and how he's just going to not fulfil his potential. DH thinks let him get on with it and fail mocks etc, so he'll see for himself. But I don't know what to do.

OP posts:
Thindog · 24/02/2026 11:56

It’s just a phase, teenagers are all vile in different ways. He may or may not fail an exam or two, but if he’s loved his hormones will settle and he will find his way.He will learn and he will grow up.

Cyclebabble · 24/02/2026 11:57

Had a similar situation with DS. He is bright and did okay at GCSE. Between then and A levels he got worse, did minimum work and also discovered alcohol and girls, which did not help. We had the talk, that he would not do as well as he would hope for or get the Unis he was looking for. He did not listen. At 17 as parents we can only guide, you cannot drag him to school or stand over him whilst he studies. He did poorly at A Level and it hurt him. We sat down again and agreed we would pay for tutors for a resit if he got a part time job. He agreed and went to work two days a week in the Co Op. He studied hard and then got into a Russell Group Uni.

He now works for a big accountancy firm and we have had a discussion that he works too hard (how times reverse..).

For us the learning point is that you can support but not direct. Be clear you will support. Equally do not judge. I made mistakes when I was his age and it is horrible watching kids make them, but they will and they need our support to learn from them.

sunshinestar1986 · 24/02/2026 12:02

Make them pay rent and bills.
They'll soon run away.
My brother did 😂
Then you can give them a nice lump.sum (unless you needed it)

neversaynevereverforever · 24/02/2026 12:09

DysmalRadius · 24/02/2026 11:37

Op, this is honestly not intended to be a 'gotcha' but in this thread you made a mistake in your OP, and when a poster pointed it out, your initial response was chippy and dismissive without actually reading what they wrote or checking what you had written.

Does that sound like your son at all?

I am only pointing this out because the number 1 thing that annoys me in my kids is when they demonstrate the behaviour traits I like least about myself.

Agree with this comment. OP your replies do come across as defensive.
My children when teenagers knew everything about everything! It’s a phase and I just generally chatted to them about their interests,friends etc .
If your son is bright and achieving his grades then I would just back off .

loulouljh · 24/02/2026 12:12

He sounds like the average teenager to me!

Comedycook · 24/02/2026 12:16

Sounds normal to me...my ds knew EVERTYTHING at that age!

blackpooolrock · 24/02/2026 12:24

reminds me of this sign...

I think it's normal for teens to think they know it all but it's hard when you can see they are wrong.

I think i would leave him to get on with his mocks and see how he goes. If he fails them he fails them. Offer help to get him back on track and go from there.

15 year-old know it all son
Freya1542 · 24/02/2026 12:27

@Spiritedlight totally relevant and just popped up here half an hour ago

SpinandSing · 24/02/2026 12:36

Astrology/Astronomy misunderstanding has given me a good giggle.

I have two dds who are a little bit like this OP - one more than the other. To be honest, she's 25 now and she stills leaps to self-defence with gentle conversations ... she can't bear for me to question anything really and never has been able to. I just totally let it go now as I can't be bothered with the conflict. I was reflecting back on her teenage years the other day and do I wish I'd challenged her a bit more? Yes, I think I do, but I'm not sure it would change the outcome. I think her personality leans towards defensive and stubborn, even though she can be lovely and sweet, and with questioning her all it will lead to is arguments and, probably, the same outcome anyway. Some people are just wired differently. We do have lots of calm conversations and she takes in a bit of experience and wisdom from me now ... but she has to be the one to invite it. It's really hard - I get it. And I am very careful with my communication style with her - I manage a lot of people and am used to different personalities ... in fact, I'm quite good at it. But kids at home ... much harder as they don't really respect your authority ... not truly. This is why they need to grow up and fly the nest! He'll resent you and just avoid telling you anything if you aren't careful.

pinkyredrose · 24/02/2026 12:44

Spiritedlight · 24/02/2026 10:14

What kind of comment is this? That's just rude

Did you mean Astronomy Op?

VenusClapTrap · 24/02/2026 12:46

Currently walking on eggshells around my 15yo know-it-all and highly combustible dd, so I sympathise. It takes some navigating. Sometimes Dh says to her ‘Now try saying the same thing, in a friendlier way’ and that does seem to give her pause.

PashaMinaMio · 24/02/2026 12:50

NoFiller · 24/02/2026 10:09

Your husband is very knowledgeable about astrology?

Not surprised your son is telling him he’s speaking bollocks.

Dear OP,
I think you meant Astronomy? The study of stars and beyond.

Astrology is quite different; the study of birth dates and signs! Check your original post. Predictive text has got the better of you!

NotSmallButFunSize · 24/02/2026 12:51

murphys · 24/02/2026 10:24

I am not sure there are many that can say they got through parenting a 15 year old boy completely unscathed.

Some will come along and say their 15 year old's were perfect specimens of the human race and they never ever pushed their luck or boundaries. To this I say that they just forgot what is was really like that year.

My ds is very sporty and was in various teams at that age. So the parents from each sport would socialise after events quite often. So there was a big ratio of 15 year old parents in one place at one time. We were definitely not alone in our thinking, and most of the boys played up in one way or another that year.

But they have mostly all turned out fine young men OP. It is just important to lay the ground rules of what is acceptable and what is not.

Well, mine was only this age last year so definitely can remember it and it honestly wasn't that bad..... 😉 Him being 3 was far worse!

That said, he is a typical teenage boy, I guess some of it is just what you are prepared to ignore. I am told he is hard working and polite outside the house so I am happy to let a lot of the grunting and eye rolling at home slide.

CustardySergeant · 24/02/2026 12:57

pinkyredrose · 24/02/2026 12:44

Did you mean Astronomy Op?

Yes, she said so in her post at 10.22.

Freya1542 · 24/02/2026 12:59

Spiritedlight · 24/02/2026 10:22

I mean astronomy!! I'm so sorry to the poster who I said was rude. I'm running into a meeting but will respond more when out

@PashaMinaMio

@Spiritedlight addressed this at 10.22 😊

Snap! @CustardySergeant

BoredZelda · 24/02/2026 13:01

15 year olds are supposed to know everything. It’s their job. Your DH is right, natural consequences are the best way.

My teenager is exactly the same, will argue black is white and has the self confidence to express her opinion. I love it, it’s what I raised her to do. Sure there are rough edges but they will be knocked off in time.

I also hate when people say their kids won’t fulfil “their” potential. What you mean is, you think he won’t live up to your expectations.

BoredZelda · 24/02/2026 13:03

VenusClapTrap · 24/02/2026 12:46

Currently walking on eggshells around my 15yo know-it-all and highly combustible dd, so I sympathise. It takes some navigating. Sometimes Dh says to her ‘Now try saying the same thing, in a friendlier way’ and that does seem to give her pause.

Urgh. Girls don’t have to be nice.

Spiritedlight · 24/02/2026 13:04

HelpMeUnpickThis · 24/02/2026 10:48

@Spiritedlight

I too would find the arrogant back chat very trying.

I agree with PP that rather than make it a debate I would just detach - grey rock, change subject etc. I wouldn’t get entangled in debates that wind me up or where I know there is a big, demonstrable difference in knowledge/experience and the other party is not open to listening or learning. I just don't have the patience for it. Same applies for adults too BTW.

I would really struggle with the lack of academic “focus”. I have put that in quotations because he might be focused but not appreciate being micro managed. Or not able to see cause and effect due to lack of experience and immaturity. For this I’d suggest you pick your hard line conversations and be less vocal about the rest. Sometimes people only learn through consequences.

Just reading your posts I do think you sound quite negative. You have repeatedly said “this is the worst stage of parenting”. Gently, your DS does not owe you a specific parenting journey. He is trying to figure himself out and let’s be honest, he doesn't really know how to do this. Your job is to support not be an oppressive critic. Try to reframe your thoughts (and perhaps words?) about how you are finding this stage of parenting. It’s quite clear you are not enjoying it. Maybe he is picking up on this low key disdain?

What I DO think you urgently need to work on is your critical or “harsh” tone, as mentioned by you. This is absolutely horrific to live with. Ask me how I know.

It’s ok to be ambitious for your son but living with someone who is constantly nit picking, correcting, giving unsolicited advice, telling you are wrong is a recipe to a distanced relationship as soon as independence is gained and years of therapy to unpick the resentment. Speaking from
lived experience.

Good luck.

Thank you for the advice and the feedback. It's sobering re: harsh tone - that said, I am VERY aware of it, he knows I'm aware of it, and it's countered by a ton of praise, love and unabashed pride in who he is. But my own traumas and upbringing certainly contributed to my directness and sharpness - it's no excuse, but it's something I am very aware of and constantly try to work on.

Thank you for the important reminder - my relationship with kids is of the utmost importance.

OP posts:
Spiritedlight · 24/02/2026 13:08

DysmalRadius · 24/02/2026 11:37

Op, this is honestly not intended to be a 'gotcha' but in this thread you made a mistake in your OP, and when a poster pointed it out, your initial response was chippy and dismissive without actually reading what they wrote or checking what you had written.

Does that sound like your son at all?

I am only pointing this out because the number 1 thing that annoys me in my kids is when they demonstrate the behaviour traits I like least about myself.

You're quite right

OP posts:
Spiritedlight · 24/02/2026 13:09

Thanks to everyone, some great thoughts here. I've only had time to skim but I'll be writing notes later.

Good to know that others are going through it

I do need to meet him with support, praise and love and let him work it out.

I need to work very hard at losing the harshness. That's what I can control. It's just my tone, never the words. But that it itself can be a barrier. I do know this.

OP posts:
Mrandy · 24/02/2026 13:11

It’s because you mean astronomy (I think!)

Friendlygingercat · 24/02/2026 13:12

Unfortunately kids who are very bright are often a bit lazy with it. Instead of planning and working towards a goal they tend to wing it and /or leave everything until the last minute. As a result they dont achieve their potential. I taught some really bright young people at uni and they rarely got a 1st. The ones who did were not perhaps quite so bright (but smarter than average) and smart enough to know that preparation and self discipline are preferable to winging it.

Julimia · 24/02/2026 13:12

You clearly have a .very normal 15 year old.Jut let him get on with it . If he asks for help thats fine but otherwise back 9ff. ¹ He will learn, so be it if its the hard way.

Spiritedlight · 24/02/2026 13:12

To clarify again (I have already clarified this) - I meant astronomy.

OP posts:
2026ontheway · 24/02/2026 13:13

murphys · 24/02/2026 10:24

I am not sure there are many that can say they got through parenting a 15 year old boy completely unscathed.

Some will come along and say their 15 year old's were perfect specimens of the human race and they never ever pushed their luck or boundaries. To this I say that they just forgot what is was really like that year.

My ds is very sporty and was in various teams at that age. So the parents from each sport would socialise after events quite often. So there was a big ratio of 15 year old parents in one place at one time. We were definitely not alone in our thinking, and most of the boys played up in one way or another that year.

But they have mostly all turned out fine young men OP. It is just important to lay the ground rules of what is acceptable and what is not.

Did you find the sport helped him (or you!) get through this stage? We’re just about to get into this stage!

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