Help end medical misogyny. Sign our petition.

Help end medical misogyny.
Sign our petition.

Sign the petition

Please or to access all these features

AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

To think "half your age plus seven" is a massive pile of nonsense?

305 replies

TransportNerd · 01/07/2026 08:07

Mumsnet seems to take a very dim view of age gap relationships, far more so than I think the general population does. I've seen plenty of age gap relationships work just fine.

Every single time they're discussed here, though, someone wheels out the "rule" that you shouldn't date someone younger than half your age plus seven years.

People treat it like it's absolutely set in stone, and that breaking this "rule" is some sort of disgusting taboo. I've even seen someone argue it should be enshrined in law, with penalties for those who break it.

Personally, I've always thought it was complete nonsense. It was simply something in a French novel in the early 1900s. It doesn't really take anything important into account, and ignores the principle that consenting adults can do what they like.

Quite apart from anything else, why is it plus seven? Why not five, eight or ten? I'm sure it's only seven because that's a number that's had mystic significance since ancient times. Not a good basis for making laws!

Anyway:

YABU - yes, it's a rule and shouldn't be broken
YANBU - it's a big pile of nonsense and doesn't mean anything

OP posts:
TransportNerd · Yesterday 15:39

OneFineDay22 · Yesterday 11:01

You never answered my question about if one of your friends started dating your 20-something year old child.

Well, there wouldn't be much I could do about it, would there?

OP posts:
kkloo · Yesterday 15:47

TransportNerd · Yesterday 15:39

Well, there wouldn't be much I could do about it, would there?

Edited

but no one on here is 'doing' anything about age gap relationships, they just have an opinion on them and that's what you seem to be complaining about. So what would your opinion be if it were your child?

TransportNerd · Yesterday 15:48

kkloo · Yesterday 15:47

but no one on here is 'doing' anything about age gap relationships, they just have an opinion on them and that's what you seem to be complaining about. So what would your opinion be if it were your child?

I'd trust their judgement and look at on its merits.

OP posts:
OneFineDay22 · Yesterday 18:32

TransportNerd · Yesterday 15:39

Well, there wouldn't be much I could do about it, would there?

Edited

I didn’t ask what you would do, I asked how you would feel.

Nervousb2b · Yesterday 19:11

What about 26 and 38? I see 27 being mentioned alot so curious about how one year younger might be perceived.

TransportNerd · Yesterday 19:21

OneFineDay22 · Yesterday 18:32

I didn’t ask what you would do, I asked how you would feel.

I don't know. Possibly OK, possibly not. I won't know unless it happens.

OP posts:
coocoocachoop · Yesterday 19:42

TransportNerd · Yesterday 19:21

I don't know. Possibly OK, possibly not. I won't know unless it happens.

Really? Do lack empathy generally if you’re not able to directly experience something before having some idea of how something could feel?

Notateacheranymore · Yesterday 19:47

I know my view could be considered a bit quaint, but most of my family and DH’s, including the 2 of us met our spouses (or at least the first ones in the case of my widowed dad and a couple of aunties), at school or within 2 years of leaving school and were within 18 months in age.

DH and I were in the same English set from Y8-11 (although it was still 2nd to 5th year then), and we started our relationship when we were in upper 6th. The amount of shared cultural experiences we have because of our similar age is very important imo, and not just there because of our shared geographical history. We have mates that I’ve known since I was at uni in1995, and this also applies. Nothing worse than reminiscing about your favourite cartoon and the other person just gives you a blank stare.

Another close friend, I met at work, is 6 years older than me and a big 80’s music fan - went to Live Aid aged 16, been to see Duran Duran over 20 times, etc and I was 9 1/2 on the day of Live Aid, which I watched avidly with my mum but there was nearly another 9 years before I started going out clubbing and the music was wildly different then.

What I am saying is- at length - is that I think I would find it hard to be in a relationship with someone who hadn’t been at a similar life stage to me during those events, even if elsewhere in the country/world.

19lottie82 · Yesterday 19:49

I didn’t think anyone actually took it seriously, did they?

WillThingsEverBeFergaliciousAgain · Yesterday 21:37

Jc2001 · Yesterday 11:51

What do you consider to be an age gap?

It depends on the ages honestly, I would consider 16 and 19 an age gap. 18 and 24, 25 and 33. Over the ages of 30 I would say 10+ years would be an age gap.

TransportNerd · Yesterday 23:02

coocoocachoop · Yesterday 19:42

Really? Do lack empathy generally if you’re not able to directly experience something before having some idea of how something could feel?

It depends on the people, not the age.

OP posts:
TransportNerd · Yesterday 23:03

19lottie82 · Yesterday 19:49

I didn’t think anyone actually took it seriously, did they?

I've seen someone on Mumsnet argue it should be made law.

OP posts:
ProBonoPublico · Yesterday 23:36

I've not read all the posts, but I've read enough to get the general feeling that the sort of age gap envisaged by the formula is far too big.

The simple fact is that it depends entirely on the individuals concerned, so that it's both impossible and extremely arrogant to prescribe a general rule. As many of the posts have proved, there are many, many relationships with large age gaps that work perfectly well despite the tut-tutting of judgmental people.

I suspect that many of those people are in unhappy relationships themselves, and are envious of couples who are happy, so try to find a reason to criticise them.

Realistically, the formula was written only to apply to men, not women, and it's far more common in such relationships for the man to be a lot older than the woman. But one advantage from the woman's point of view is that her hubby is likely to kick the bucket and leave her a hefty inheritance while she's still young enough to enjoy it!

coocoocachoop · Yesterday 23:54

TransportNerd · Yesterday 23:03

I've seen someone on Mumsnet argue it should be made law.

And do you take people this literally in real life?

coocoocachoop · Today 00:06

TransportNerd · Yesterday 23:02

It depends on the people, not the age.

Hmm. I do wonder if you’d be as liberal as that if it was your own child. I know I wouldn’t be, that’s just honest.

feellikeanalien · Today 00:12

DP was 8 years younger than me. It's a load of nonsense.

OonaStubbs · Today 00:16

I think it should be made law. It would stop dirty old men from taking advantage of innocent young girls, and also prevent gold-digging jezebels from marrying geriatric Texas oilmen and stealing their children's rightful inheritances.

TwoLeftSocksWithHoles · Today 00:19

I thougt that the only reason we were taught Quadratic Equations at school was to be able calculate the maximum acceptable age gaps.

Unfortunately I have forgotten how to do them, so rely on my logarithms table - and I'm not much better with them.

mondaytosunday · Today 00:32

Never heard of that. I’m 64, so half my age plus 7 is 39 and not sure that makes sense at all. Though 30 dating a 22 year old doesn’t sound so bad.

kkloo · Today 01:41

TransportNerd · Yesterday 19:21

I don't know. Possibly OK, possibly not. I won't know unless it happens.

And if you had an adult child 30+ and they introduced you to their 18 year old girlfriend?

wheresthesnowgone · Today 06:42

DarkForces · 01/07/2026 08:18

I think most mumsnet rules are safely ignored. Life would be very dull and toilet brush manufacturers would be broke if we all followed them

And you'd never be able to date someone your sister once looked at.

TransportNerd · Today 08:06

coocoocachoop · Yesterday 23:54

And do you take people this literally in real life?

Well, the person I was talking about who has repeatedly and seriously argued it should be made law has just predictably reappeared to do so again.

OP posts:
OneFineDay22 · Today 08:25

kkloo · Today 01:41

And if you had an adult child 30+ and they introduced you to their 18 year old girlfriend?

Yes, and this

TransportNerd · Today 09:24

wheresthesnowgone · Today 06:42

And you'd never be able to date someone your sister once looked at.

😂

OP posts:
Loveandheights · Today 09:33

People on mumsnet have had kids and seen it all. They aren’t judging, they know you’re getting used. We look back on earlier years and dynamics and see the truth. We’re also old enough to watch our 40M friends try to date women in their early 20s and see how unbalanced that is. You’ll understand one day. If you love the person enough, go for it despite what anyone says. Everyone lives and learns through this process.

Swipe left for the next trending thread