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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:
LidlAmaretto · 24/02/2026 17:18

Firebox64 · 24/02/2026 17:13

Arguing with a teenager is like mud wrestling with a hog. You both get covered and the hog loves it.

LOL brilliant and so true!

poke955 · 24/02/2026 17:21

Reading this thread, and wondering if some men just don't grow out of it... 😅

Cherrysoup · 24/02/2026 17:24

‘I am not young enough to know everything’ as the play has it! None so cocksure as some teenagers.

MummyWillow1 · 24/02/2026 17:37

Spiritedlight · 24/02/2026 10:05

With respect, that doesn't really help me.

It isn’t meant to help you. It is meant to help him.

Stop talking at him and start listening.

sellersvin · 24/02/2026 17:52

LidlAmaretto · 24/02/2026 17:18

LOL brilliant and so true!

😁

TheIrritatingGentleman · 24/02/2026 17:52

ThePerfectWeekender · 24/02/2026 10:15

Astronomy or astrology? No wonder DS is mocking DH.

You don't think it's rude for a child to mock their parents?

Sensibletrousers · 24/02/2026 18:05

A question for you to consider: is he seeking victory, or accuracy? They can seem the same to the onlooker, but are very different drivers.

Does he want to “win” an argument, or prove someone wrong, for the sake of winning… or does he simply have a deep need for facts and absolute accuracy?

I can come across argumentative / opinionated / pedantic but I don’t care at all about winning or being the cleverest. I just really care about accuracy so if someone makes a bold statement based on dodgy misinformation, outdated or disproven science / data, or just on their feelings I feel the need to add actual facts to the mix! I realise it is annoying so censor myself and only speak up if it really matters….. I also LOVE IT if someone proves me wrong with better facts / accuracy and I gladly change my opinions whenever that happens! This is hopefully one of the skills your son will develop as he matures!

In the meantime my advice (I have two teen boys) would be this: let him. Let him FAFO in as many situations as you can whilst staying safe. Let him do things his way and either succeed (great! He was right!) or fail (great! He will learn!)…. And stop engaging in discussions he cannot be swayed on.

Pick your battles and change the subject.

Banannanana · 24/02/2026 18:05

I think this is pretty typical for his age, I know that doesn’t make it less irritating for you though!

Defence mechanism is spot on I’d say. Leave him to it for now, he’ll get a wake up call before the exams (mocks are usually it!). Just pick your battles and right now this isn’t one worth having. If he’s getting the grades he needs to make the next step in his life that’s enough for now. It’s him who has to live with it if he doesn’t get what he wants.

I’m not usually an advocate for hands off parenting and I do feel for you, I can imagine it’s irritating, but if he’s not doing too badly or behaving badly I’d just leave him to it for now and hope he gets a wake up call soon. He may be panicking more than he’s letting onto you anyway, that’s common with boys of his age.

ccridersuz · 24/02/2026 18:11

First off, all teenagers at 15 know everything, no matter the subject, it’s pretty common to be informed of your lack of knowledge by a 15 year old. The other problem is the other 15 year olds that are not your kids, also know everything, so the problem is magnified and cannot be argued against.

The issue is trying to get a 15 year old to do homework, you have more chance of experiencing the second coming!.
There’s only two things that get homework done by a 15 year old, bribery or blackmail or a bit of both!.
As their parent, you have to figure out what’s gonna work and what won’t.
Mine (twins) were open to a bit of both, bringing out baby photos worked a treat and a new Xbox game had the desired effect.
As for being outright rude or bad mouthing anyone, that resulted in a punishment.
They may be 15, but they are still, your kids and must accept your rules.
Mock exams are a wake up call for many, especially if compared to their brainiest friend.
But, we also have to remember that they may not be academically inclined, but will find their way in other aspects of life.

Breadcat24 · 24/02/2026 18:11

Have a friend's son that was like this- his mocks knocked the stuffing out of him, and made hiim study

justasking111 · 24/02/2026 18:33

Three boys here. They're really not designed to study ten subjects I decided. They shine more at A level when they choose something they are really interested in.

As a girl who was a swot my DH explained that was normal.

MMUmum · 24/02/2026 19:21

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.

Tell him he's welcome to state his point of view as long as he can back it up with evidence, then he would have to study and might even find out he's not always right, Also good practice for essays in later studies.

ThatLilacTiger · 24/02/2026 19:22

Spiritedlight · 24/02/2026 10:17

I don't know how that one sentence of yours could make me reflect, in any way.

That said, your comments here resonate. I do think my tone can be quite harsh sometimes and he points it out and I always apologise. We are very good at 'repair'.

That said, he gets tons of praise and nurturing and we are always talking

Honestly you come off pretty aggressive in this thread and your son is telling you the same thing. Maybe you should listen.

NoFiller · 24/02/2026 19:45

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

No worries.

I made the original comment because I’ve always thought astrology is a load of bollocks. That’s because I’m a Scorpio and we’re analytical and scientific evidence-based.

Noodledog · 24/02/2026 19:51

It's a phase, just a particularly annoying one. I'd try to approach with tolerance and some mild piss taking.

The 19th century writer Mark Twain said:
When I was a boy of 14, my father was so ignorant I could hardly stand to have the old man around. But when I got to be 21, I was astonished at how much the old man had learned in seven years."

It will pass!

justasking111 · 24/02/2026 20:50

Noodledog · 24/02/2026 19:51

It's a phase, just a particularly annoying one. I'd try to approach with tolerance and some mild piss taking.

The 19th century writer Mark Twain said:
When I was a boy of 14, my father was so ignorant I could hardly stand to have the old man around. But when I got to be 21, I was astonished at how much the old man had learned in seven years."

It will pass!

My dad taught me that quote

MissRaspberry · 24/02/2026 21:56

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.

I mean to be fair he sounds like a typical teenager. The all like to think they know it all at that age. Does he get consequences for actually back chatting because to be honest I wouldn't be putting up with him telling his dad he's "talking bollocks" without actually telling him about himself. It's one thing thinking he knows it all but it's a whole other story him thinking he can be a cocky rude little shit just because he may think he's more intelligent than his parents. Whilst he may be smart it doesn't excuse his rudeness to his parents. My son is almost 16 and he's a smart kid but he knows he should still speak to me respectfully even if I'm not as knowledgeable as he is

CrazeeMamma · 24/02/2026 22:52

My DS was similar, but not quite so bad, at that age. It's a very difficult time with a combination of adult feelings/hormones competing with juvenile feelings etc. So a bit of 'taking a deep breath' is needed.

The best time to talk to my DS was when there was just two of us in the car and I was driving, we had our best conversations on those journeys which were long enough to talk.

I said to him "yes you're clever, you're intelligent and you're doing well, without really having to try" but those who are less clever but are trying hard are learning how to study and at some point, they will overtake you because they have developed those additional skills. Imagine how well you could do if you also push yourself."

Then leave it, let the words settle and he'll ruminate on them. He'll do his own thing, in his own way. Reassure him that you'll be there to support him and try to spend time just you and your DP together, sounds like you need some 'you' time aswell.

VenusClapTrap · 24/02/2026 23:01

BoredZelda · 24/02/2026 13:03

Urgh. Girls don’t have to be nice.

Being rude and unpleasant to family members is unacceptable, whether coming from a girl or boy. If ds starts doing it when he gets to the same age, he will be asked to be ‘friendlier’ too.

Dogmum6 · 25/02/2026 08:34

Ask chatgpt about the 15 year old developmental 'know it all' phase and why they can't take advice. It's an interesting answer (sorry too long to copy).

foxbasesecular43 · 25/02/2026 09:41

murphys · 24/02/2026 10:12

15 year old boys and generally a bit of a nightmare OP.

The year that my ds was 15, the parents of the whole year were called in to the school at the start of the year. We were told that this could quite possibly be one of the hardest years of parenting due to their age. Hormones, changing bodies, the odd age of not a child and not an adult, so they don't quite know where they fit.

You and dh need to be a team and set good boundries. And then grit your teeth a lot and in a year or so, he will become pretty nice and normal again.

100% agree with this his comment. The OP could have been writing about my DS when he was 15 - it was maddening. He's now nearly 18, and life is humbling him by itself, we don't need to play any part in it. The cockiness was self protective behaviours, and through endless communication and giving him clear boundaries we now have a kid who is smart, opinionated, occasionally cocky but mainly really fun to have around and I'm sure an interesting character to those who give him the time and space he deserves. Some people wont like it, other people will. It's just one of those traits of character.

Spiritedlight · 25/02/2026 11:38

Thanks to everyone again for adding to the thread. I've taken it all on board. I don't mean to come across as aggressive, I don't think I am, but I am also not avoidant, and if I don't agree with a post, I think it's ok to say.

We had a really good evening last night where I took some of the advice here and just rolled with it all, gritted teeth where necessary, praised him to the enth degree and let him get on with it. So, thanks to all

OP posts:
sellersvin · 25/02/2026 13:09

Spiritedlight · 25/02/2026 11:38

Thanks to everyone again for adding to the thread. I've taken it all on board. I don't mean to come across as aggressive, I don't think I am, but I am also not avoidant, and if I don't agree with a post, I think it's ok to say.

We had a really good evening last night where I took some of the advice here and just rolled with it all, gritted teeth where necessary, praised him to the enth degree and let him get on with it. So, thanks to all

How did he respond?

pinkyredrose · 25/02/2026 14:24

NoFiller · 24/02/2026 19:45

No worries.

I made the original comment because I’ve always thought astrology is a load of bollocks. That’s because I’m a Scorpio and we’re analytical and scientific evidence-based.

😂

Spiritedlight · 25/02/2026 15:06

pinkyredrose · 25/02/2026 14:24

😂

😂

OP posts: