Meet the Other Phone. Child-safe in minutes.

Meet the Other Phone.
Child-safe in minutes.

Buy now

Please or to access all these features

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:
LardyCakeLover · 24/02/2026 14:11

frozendaisy · 24/02/2026 10:13

Yep let him fail his mocks he will have to turn it around if he wants to

at least then you will have lower marks in black and white to suggest perhaps more effort and the teacher’s advice could be listened to

We took this approach regarding failing mocks. Unfortunately, COVID hit and our sons A level results were largely based on the mock results. Had to spend another year at college to re-sit.

RobinEllacotStrike · 24/02/2026 14:12

NamingNoNames · 24/02/2026 14:03

@RobinEllacotStrike , that quote has already been posted on page 2.

what a pointless thing to say

NamingNoNames · 24/02/2026 14:13

RobinEllacotStrike · 24/02/2026 14:12

what a pointless thing to say

What a pointless thing to say.

Franjipanl8r · 24/02/2026 14:18

Do you actively listen to what he says or just always give contrary opinions? My parents are incapable of just saying “yes dear” or “I hear what you’re saying” or “oh that sound difficult”, all they do it just tell their own completely irrelevant stories and throw in constructive criticisms. It’s infuriating and often results in just constantly trying to reaffirm my opinions.

Dollymylove · 24/02/2026 14:25

He sounds like most teenage boys, to be honest 😅

Maray1967 · 24/02/2026 14:26

I’ve been through this twice. My advice is to breathe deeply and step back.

That is also my advice as an HE first year course lead. The students who struggle the most, aside from those with very serious personal circumstances, are the ones whose parents dragged them through GCSEs and A-Levels and who have no self discipline. Now is the perfect time for him to
learn some lessons. If he under performs in the mocks it should provide a wake up call.

RideMeSidewaysWasAnother1 · 24/02/2026 14:34

No words of wisdom OP but I'm in the trenches with you. Almost 14year old here and he was shocked the other day that we knew what the word cringe meant 🤣.

sellersvin · 24/02/2026 14:38

Muffinmam · 24/02/2026 13:22

He doesn’t sound smart - he sounds narcissistic.

An intelligent person doesn’t argue about things they know nothing about.

My brother was/is incredibly intelligent. He was gifted as a child and coasted through school without any effort.

He argued about things he knew about and as an adult he is extremely well read and now works in a STEM field.

The problem with gifted children is they can burn out after highschool. They grow up knowing they were the smartest in their entire school and never had to try. At University they are often not the smartest and need to actually show up to lectures or they will fail.

There’s also the possibility that a person can be so intelligent they can feel ostracised from their peers and suffer terrible mental health.

I don’t think your son is at any risk of either of the above scenarios.

I suggest you encourage your son to pursue a trade if his grades are bad. Also, if he’s arguing about things he has no knowledge of he will completely fail at University as no one will put up with his BS.

As a parent it is your responsibility to prepare your children for society’s expectations and part of that is social intercourse. Without social skills he will fail to establish a social network at University or in any workplace which will very much limit his career options.

ASD?

sellersvin · 24/02/2026 14:39

sellersvin · 24/02/2026 14:38

ASD?

Loving "social intercourse"

Hankunamatata · 24/02/2026 14:40

I find

'Your being bloody rude right now, we will speak later when you can use your manners'

And walk out the room (yes im a teen parent on the edge lol)

UnctuousUnicorns · 24/02/2026 14:41

RideMeSidewaysWasAnother1 · 24/02/2026 14:34

No words of wisdom OP but I'm in the trenches with you. Almost 14year old here and he was shocked the other day that we knew what the word cringe meant 🤣.

Edited

😅 Aye, but in my day 👵 it was a verb, nowadays it's a semi noun a là "I nearly died of cringe!" 😂

Vaxtable · 24/02/2026 14:45

Team DH. Stop chasing him, let him fail

Flapjak · 24/02/2026 14:48

RosesAndHellebores · 24/02/2026 10:24

@Spiritedlight this too shall pass. At 15 DS would argue the wall was black, not white. We tried hard to deflect the comments but it was a challenging time with little or no listening to other perspectives. He had uncontestable views based on many things: politics, the police, social justice, liberal arts v stem, his headmaster, whether the sun was fucking shining.

He's 31 now, married, expecting a baby and has a PhD. He started to revert to his chilled, sunny self when he was about 22, getting back to base at about 25 when I think the frontal cortex is fully formed. Be glad he has the confidence in his nurture and security at home to kick off at home. At this stage it's all about the export model.

Oh gosh , I have one of these , please don't tell me there is another 8-10 years of this to go . I feel I gave lost my relatively easy going and reasonable child to a cold, unempathic, bullish know it all and am not quite sure how to approach it. Currently on the recieving end of silent treatment for trying to set some boundaries

Hazjack · 24/02/2026 14:52

My 13 year old son is like this already. I just smile and say you're free to believe whatever you wish darling

BunnyLake · 24/02/2026 14:53

Spiritedlight · 24/02/2026 10:14

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

I think you probably meant astronomy, not astrology (which is pretty much bollocks).

TheMousePipes · 24/02/2026 14:55

Nofeckingway · 24/02/2026 10:53

This

We had this painted on the wall in the staffroom in a school I once worked in.

I have no sage advice, but fucking hell it's hard work. They are just SO informed about ALL the things and parents are just annoying and stupid and GODDDD stop talking MUTHER.

Sending solidarity. This too shall pass.

BunnyLake · 24/02/2026 14:58

Muffinmam · 24/02/2026 13:22

He doesn’t sound smart - he sounds narcissistic.

An intelligent person doesn’t argue about things they know nothing about.

My brother was/is incredibly intelligent. He was gifted as a child and coasted through school without any effort.

He argued about things he knew about and as an adult he is extremely well read and now works in a STEM field.

The problem with gifted children is they can burn out after highschool. They grow up knowing they were the smartest in their entire school and never had to try. At University they are often not the smartest and need to actually show up to lectures or they will fail.

There’s also the possibility that a person can be so intelligent they can feel ostracised from their peers and suffer terrible mental health.

I don’t think your son is at any risk of either of the above scenarios.

I suggest you encourage your son to pursue a trade if his grades are bad. Also, if he’s arguing about things he has no knowledge of he will completely fail at University as no one will put up with his BS.

As a parent it is your responsibility to prepare your children for society’s expectations and part of that is social intercourse. Without social skills he will fail to establish a social network at University or in any workplace which will very much limit his career options.

Never mind your brother what about your teenage son? What is he like, or was like if he’s older now,

TheMousePipes · 24/02/2026 14:59

There was a picture up thread I wished ti quote. I give up.

LostInTheDream · 24/02/2026 15:00

Maybe he will do badly in his mocks and maybe he won't. If he does well it may validate his views, for a while at least. A levels might be a totally different situation again though.

The future goals is great, but a lot of kids don't actually know and it's good not to close too many doors too early.

I'm never too sure if failing is a valuablele life lesson or just a dent to self esteem. Either way, I think it's sometimes something you have to experience yourself as that is how you gain the wisdom.

LidlAmaretto · 24/02/2026 15:04

KaleidoscopeSmile · 24/02/2026 11:02

Some other smartarse has already said this. Why not just assume that she meant astronomy?

It did make me laugh to think of a grown man having an argument with his DS about whether being a Gemini really makes you indecisive!

Nos4r2 · 24/02/2026 15:06

My DH's Nephew was a cocky know it all at that age, then he grew out of it and became a lovely boy, but now he is in a relationship with 2 kids and he has turned back into a know it all again. He is very annoying and boring at the same time

TheChickenOrTheMiniEgg · 24/02/2026 15:17

BlueMoonBlueCheese · 24/02/2026 10:15

Maybe it was intended to make you reflect.

Why does he think you are telling him off?

Children's communication skills are a reflection of their parents communication skills or lack thereof.
Maybe you don't realise it but the tone you are using is critical, negative etc.
Maybe you never praise him, it's hard for any reader to say with the limited information.
Maybe try and take him for a meal or a walk and talk about the good things in his life and gently try and find out if there is anything worrying him?

Haha you win today’s pomposity award!

Spiritedlight · 24/02/2026 15:20

HelpMeUnpickThis · 24/02/2026 13:39

Hi @Spiritedlight

I am NOT trying to pick on you but please do whatever you can to sort out your own childhood / upbringing issues so that you don’t pass on the trauma to your son.

You say you are aware that your background affects how you speak / interact with your son. If so - then do something about it.

Don’t pass the trauma down.

Edited

I have had lots of work on myself. Thank you.

OP posts:
smurfingbutgenerallynice · 24/02/2026 15:23

I have experience of this. I think teens talk like this when they are very stressed, they know they have left things to the last minute, they are anxious about the future, they know they haven 't done enough work, things like that. But they won't say that and in fact may not even have processed the thoughts fully enough to be able to give them words.

I suspect that your dc knows that they are clever but they also feel anxiety, perhaps about being behind.

In relation to the astronomy discussion, your dc is arguing and perhaps making things up because he wants to know about it and wants to have an intelligent discussion about it. So buy him a dk encycopeadia of space, it is brilliant and full of engaging fascinating info. And buy him other dk's while at it.

Your dc probably feels threatened by your dh for good reason on some level so worth thinking that through

Teens who coast (do well enough without trying at all - but not as well as they could) won't find their passions unless they really put their heart and soul into their learning. Coasting is not doing them any favours. I think it is worth talking about this and saying that you can support your dc's learning and that you can help him do well and say it a lot until it gets through

I wouldn't let your dc fail his mock to show him, it will affect his confidence and stress levels and make it even harder to revise.

While waitiing for him to listen, you could have a look at his work and make a plan for each subject about what you think needs doing to get him up to speed, and think of nice bribes to motivate each stage and then just force it through with him, getting him to learn bits with rewards at a time until his natural self motivation comes alive. I realise they are 15 but this is a hard time to be 15 and there will be a lot of influences in their lives taking them in the wrong direction.

It isn't a boy/girl thing incidentally. Girls are like this too if they know they could do well and secretly want to do better but feel a bit behind and stressed out.

Calliopespa · 24/02/2026 15:26

Toddlerteaplease · 24/02/2026 10:11

A friends son is exactly the same. His parents just laughed it off and said he was going to be a politician, but I found annoying and rude.

I have known many boys to be a bit of a know-it-all at that age, just as I have known girls to be scowling and touchy (and a few know-it-alls). It's both hormones and a part of the natural move to break away from parental control/opinions/values and to see themself as a competent individual with their own ideas. They resent input for biological reasons of needing to grow less dependent on it.

Sadly, I think sometimes the dc who have been closer to their parents/ more amenable have more need to make the break to independence of thought and can be worse, which can come as a shock.

Swipe left for the next trending thread