[tn13]

Main stream journalists can not get science right.

In the normal course of evolution women with narrower pelvis die a painful death while delivering a baby (or the baby dies). Thus the genes that give women a narrower pelvis do not get passed on.

We can not let these women die this horrible death. This is a good outcome.

[corin_]

"Women with a very narrow pelvis would not have survived birth 100 years ago. They do now and pass on their genes encoding for a narrow pelvis to their daughters."

and

"Our intent is not to criticise medical intervention," he said. "But it's had an evolutionary effect."

The article said everything you said, and more, in what way did it "not get science right"?

[3chelon]

To be fair, aside from the preschool formatting of the article (one sentence per paragraph, a concerning recent BBC trend), the journalist didn't actually say anything incorrect.

But she did not answer the main question that was asked: why the human pelvis has not grown wider over the years? She said that there were two opposing forces, one for larger babies (they have more chance of survival), and the other was natural selection preventing them getting too large (by killing them both in childbirth).

Maybe I'm missing something, but neither of those answer the question of why the pelvis has not got larger.

All I can assume is that it is (a) an evolutionary trend of men to be attracted to younger and potentially, on average, slimmer and more healthy or fertile women, and (b) cultural, since there is evidence that in historic times and possibly also in less technologically advanced societies, larger hips are considered desirable (which makes total sense in a society with no access to modern medicine).

I'm sure some anthropologists will beat me up for these terrible generalisations, but in general, on average, it seems these forces may have an impact on pelvis size over generations?

[marchenko]

Men are indeed attracted to relatively wide-hipped women, but there is an upper limit on hip width. There is a biomechanical tradeoff between pelvic shape and locomotor efficiency. The width of the pelvis affects the energy needed for a bipedal gait, since it alters the shape of the largest bones of the lower skeleton and their associated musculature (compare the angle of the femur in men v women and imagine how it affects joint stress). So there's a three way evolutionary arms race between the needs of the large-brained infant, the need to successfully expel said infant, and the need to be able to walk and run efficiently and without musculoskeletal damage.

[Swizec]

> one sentence per paragraph, a concerning recent BBC trend

3 of your 5 paragraphs are a single sentence.

[3chelon]

Yes, deliberately, and not all of them. And my post contains far fewer sentences than the article.

[Swizec]

Funnily, those 3 paragraphs - because they were long sentences - were the easier to read on mobile. So there's one datapoint for ya.

[throwawygybj]

There's two sides to this coin. By allowing normally lethal genes to be passed on were likely to cause more death in the future. This is definitely something that should be screened and prevented, whether through gene editing, surrogacy, or just selecting for embryos that are either male or lack the undesired trait.

Nobody has to die to voluntarily select this out of the population. The Jewish community has been on the forefront of this for a long time. On the border of eugenics I guess, but self selecting against genes that will cause suffering or death.

[curun1r]

Why should we avoid those genes? We have the technology to deal with the situation when it arises. What would be the problem with, eventually, all women giving birth by Caesarean?

There are plenty of other instances where our advancements have likely influenced our evolution. For one, the ease at which we can today travel between continents means that there's far more breeding between different races than we've ever had in human history. Should that be stopped? We also don't run/walk nearly as much as we used to thanks to harnessing hydrocarbons...should we continue to try to select for the long-distance running abilities that helped our ancestors kill animals for food during persistence hunting? And I'm betting that certain people are genetically more predisposed to catching measles, polio or any of the other diseases for which we've developed effective vaccines...would we want to make sure that those genes don't get passed on?

In short...why optimize for a world that doesn't exist? Unless you subscribe to a belief in a post-apocalyptic future where modern technology regresses and mankind is forced to live in a more primitive state, there's really no need for us to actively do anything...the magic of evolution is that it just happens naturally. Now, evolution can be an uncaring bitch to individuals, so there's plenty of reason why an individual would want to screen their offspring for certain genetic traits, but at the societal level, it's just swimming against a really strong current.

[ominous]

> What would be the problem with, eventually, all humans needing glasses to see, or born with cornea defects? We know how to fix that.

We should optimize for a world that works, instead of one we believe we'll be able to fix forever, and constantly requires purposeful effort to work. Would you like to carry your Fix The Generalized Imbalance Pills (FTGIMP, f-gimp how we call it, as in: "Hold on love, the trekking has been fun, but know I gotta take the f----gimp") when you decide to go for a bike ride? Or will you tell me "but how many people do you know that go on bike rides for more than 10 minutes?". How many people travel the world on a shoestring? Should they stop doing that?

Would you like to go to space? How large should the infirmary be? With all these things that "we know how to do" and will be required to do, if we don't get a better vessel.

I agree the world has changed. But this vessel is still better when it is self sufficient to the max. Instead of long distance running, we will need low maintenance living. Requiring vaccines, failing joints, birth complications will not help. The resources are limited. It helps no one, in the long run, to make living more complex.

[lostlogin]

The advances you seem to think are bad lead to those who benefit from treatments being productive. They build stuff and contribute and this helps society. It helps everyone when you help those who are infirm/unwell/unlucky. But say we took the view that intervention was bad - who chooses who dies?

[zde]

> What would be the problem with, eventually, all women giving birth by Caesarean?

It needs significantly more resources (time, labor, medication) and therefore should negatively affect host's fitness but in most developed countries it does not. NOW we optimize for a world that does not exist.

[lostlogin]

It requires a lot less resources than a painful death uses. It also uses less resources than a vaginal delivery that should have been a ceasar. How are we optimising for a world that doesn't exist?