Title's a bit misleading. The study actually found that mothers with a low waste-hip ratio had smarter kids. That translates to big hips (and narrow waist), not the image of rolls of fat and a gigantic gut that normally come to mind when you say "fat moms".

Also, I'm curious if they actually measured polyunsaturated fat levels and correlated them. I've heard other studies that suggested big hips lead to healthier, smarter children because they lead to easier childbirths and inflict less trauma on the fetus during delivery. They could control for this by testing a group of kids delivered by caesarean.

I changed it.

Everyone post how curvy your mom/mum is to see if we can verify this

No one else took you up on this, but my mother is definitely curvy.

John.

OK, now I know why no one else replied. I feel weird about talking about my mother that way.

Correlation != Causation

It drives me crazy when I hear stories about "Children who [play an instrument / listen to classical music / have a pet] are smarter than average".

While that itself may be true, the implication that one causes the other most likely isn't. It's far more likely that a kid is smart AND plays an instrument or listens to classical music because their parents foster that sort of environment.

If your kid is dumb, making him listen to classical music isn't going help. There was a great Penn and Teller "Bullshit!" episode about this: http://www.sho.com/site/ptbs/prevepisodes.do?episodeid=s1/bb

Humans are born as physiological fetuses to allow further growth of the skull. There is a natural limit to how early a child can be born, and therefore a natural limit on the size of heads. Human females have adapted wide hips to account mainly for the size of the brain, but there is a practical limit to that as well. The cesarean section will perhaps allow further increase in human intelligence.

If the hip-fat theory is correct, then other bodily fats should have a similar effect. I am guessing I could find data that suggests large-assed females actually have children with lower IQs, though I doubt I could get a grant for that.

Or maybe smart men marry curvy women. At least that's what I did.

evolution at its best. survival of the curvy-est.

Studies like this have a simple formula:

Find a correlation.

Make up a cause.

Pretend the correlation implies that cause, when in fact they have found absolutely zero evidence whatsoever of their conclusion.

Get published.

Have you read their paper?

No. It requires registration and is unclear on whether I will have to pay to read it.

I have read many other papers.

Have you read it? Is the linked article misleading and it's actually good?

Here's the abstract:

Upper-body fat has negative effects and lower-body fat has positive effects on the supply of long-chain polyunsaturated fatty acids that are essential for neurodevelopment. Thus, waist-hip ratio (WHR), a useful proxy for the ratio of upper-body fat to lower-body fat, should predict cognitive ability in women and their offspring. Moreover, because teenage mothers and their children compete for these resources, their cognitive development should be compromised, but less so for mothers with lower WHRs. These predictions are supported by data from the Third National Health and Nutrition Examination Survey. Controlling for other correlates of cognitive ability, women with lower WHRs and their children have significantly higher cognitive test scores, and teenage mothers with lower WHRs and their children are protected from cognitive decrements associated with teen births. These findings support the idea that WHR reflects the availability of neurodevelopmental resources and thus offer a new explanation for men's preference for low WHR.

Yeah I saw that. I don't think we can tell much from it. Do you think it's revealing?

It doesn't seem like they show evidence for anything more than significant correlation. Other theories (like birth trauma reduction) could explain it just as well.

This thread is a good example of why I don't usually comment on YC. People don't take the discussions seriously enough. They ask a question and don't followup. It's not worth explaining things carefully here.

Web forums need better notification when someone responds to you. And each site has to reinvent the wheel. I remember people asked for this for months on reddit before it got the little envelope icon.

It's just too bad.

I read good explanations... so please keep posting 'em

Who cares? I'll take the hot wife and the dumb baby.

Still trying for the record eh?

Yes, and failing miserably. I guess there's a rift between people who have a sense of humor and those who don't. I need to find a way to get both to downmod me.

I thought it was hilarious. Then again I don't even see where to downmod, so my only choice was vote up.

It was kinda the obvious joke there. But funny. And true.

And you gotta do something ;)