
Caesarean births 'affecting human evolution' - MichalSikora
http://www.bbc.com/news/science-environment-38210837
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SocratesV
Going to potentially be controversial, but we need (might be a strong word
here) genetic manipulation with strong ethical and humanist values attached to
it (and a lot more knowledge).

If we are to deny natural selection its role, then we might want to still
prevent people from passing on genes which effectively handicap them when they
don't have access to certain facilities and technology. Prevention in this
case is not eugenics, but gene manipulation/therapy.

Having said this, what we most certainly don't want is genetic standardisation
(good path for extinction) and even the manipulation of genes, that seem to
cause "problems" (today's problems might be tomorrow's cure), needs a deep
understanding of implications, which at the moment we probably don't have.

P.S.: Hold the similar view regarding GMO in food.

~~~
Grangar
I'm no evolutionary scientist, but haven't we as a species already denied
natural selection long ago?

For evolution you need physical separation. With our level of globalisation
that's not going to work.

~~~
qb45
> For evolution you need physical separation. With our level of globalisation
> that's not going to work.

Global empires are nature's way to shuffle some genes around and reduce
inbreeding. Then individual nations start to exploit the empire for their
selfish benefit, everything falls apart and nature runs an iteration of
competitive evolution for a change. Rinse, repeat.

Disclaimer: talking out of my ass :)

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gadders
The other medical intervention that is affecting evolution is ICSI
([https://en.wikipedia.org/wiki/Intracytoplasmic_sperm_injecti...](https://en.wikipedia.org/wiki/Intracytoplasmic_sperm_injection))
iVF treatment where the man has low quality sperm.

I've heard that the doctors who perform this joke that they are breeding
future clients for themselves.

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grondilu
Couldn't this be said about medicine in general?

~~~
gmac
Yes. The better medicine gets, the feebler we all become. This is a pity, but
the alternative is worse[1].

[1] [https://www.quora.com/Are-we-eliminating-natural-
selection-b...](https://www.quora.com/Are-we-eliminating-natural-selection-by-
helping-the-poor-the-ill-and-the-weak)

~~~
lostlogin
It's not a pity at all. Everyone who is around that wouldn't be without modern
medicine imparts something to those around them. To give an extreme example,
Stephen Hawking.

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UweSchmidt
Do we really need caveman-capabilities? To be ready for the day we lose our
tech and have to start over?

In a different context it has been discussed how we have used up our easily
accessible energy and may not be able to restart civilization on this planet.
So why keep lowtech genes around? Make way for large brains and large heads!

~~~
3chelon
I think maybe in the back of everyone's mind is the post-apocalyptic scenario.
Which is strange, because at at that point we'd have far greater worries, such
as lack of food, clean water and antibiotics.

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entranceright
The way we live is very unnatural. That's why it is only logical that also our
evolution is unnatural. Since we no longer have any natural enemies, we
ourselves set up the rules, that decide over life and death. And these rules
are wrong in many ways. You could write a whole book about it.

One chapter could be devoted to the resulting overpopulation that causes a
variety of problems. Instead of letting politics, medicine and capitalism
dictate our evolution, we should give nature more freedom. And if we further
succeed in reducing the world population to 3 or 4 billions, a certain
equilibrium could be reestablished in this world. I am ready to help.

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JoeAltmaier
Humans have been evolving more in the last 50,000 years that in the previous
million (by bone records). This is nothing new. Social organizations
(tribe/village/town/city) have put new pressures on us to adapt to.

Never mind caesarean; why do so many people need glasses? Why do so many get
depressed in winter? It may all be ad-hoc sledgehammer adaptations to get
(most of) us to settle down in villages and specialize. And use less calories
per capita so the village thrives, even at the expense of the comfort of
individuals.

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32h8
Evolution is a ultimate rat race.

FYI offtopic: Kid can be mingled in umbilical cord and natural birth is not
possibile then. Only way is caesarean. Dont pull the baby by the head.

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3chelon
It is blindingly obvious from an evolutionary standpoint that this is
happening. I have thought about it a fair bit, as it has directly impacted my
own family, and I've no doubt it will continue to do so in subsequent
generations.

I don't think it's something to worry much about, as the much broader benefits
of modern medicine (namely, antibiotics) have had so much impact on our
survival rate that this would pale into insignificance.

Which may be borne out (pun intended) by the numbers: 3% to 3.3% or 3.6% in
50-60 years - is that statistically significant? The error there is in the
same order as the overall increase, so it's hard to believe it's even
measurable at this stage.

Because it is so obviously going to happen, I suspect there may be some curve-
fitting going on here?

~~~
Noseshine

      > 3% to 3.3% or 3.6% in 50-60 years - is that statistically significant? 
    

Since all births are recorded, the sample size is very large. So without
having the numbers and doing any calculations, just based on that I'm pretty
sure even a much smaller increase would still be statistically significant.

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foldr
>Researchers estimate cases where the baby cannot fit down the birth canal
have increased from 30 in 1,000 in the 1960s to 36 in 1,000 births today.

This could easily be explained by doctors being more willing to perform
Caesareans than they were previously. No evidence is cited that the average
width of women's pelvises has actually changed, so this is all wild
speculation as far as I can see.

Of course, it is no surprise to see the HN crowd latching on to the idea that
we should let more women die in childbirth.

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aplomb
Modern anything affects human evolution - food production, social programs,
culture, etc.

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fyhhvvfddhv
Call me a sceptic.. since the invention of farming women have had little
evolutionary pressure to run fast to catch food nor outrun predators. Why then
haven't evolution widen the canal to reduce fatalities during childbirth? And
this has been going on for much longer than caesarean procedures.

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amelius
I personally blame advertisment photography, with their models with
ridiculously close-to-one waist/hip ratios.

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pjc50
Flagged for political content (eugenics, reproductive ethics).

~~~
Chris2048
Do you still call chemistry "Alchemy"? Because this isn't Eugenics.

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bambax
> _Historically, these genes would not have been passed from mother to child
> as both would have died in labour._

How do we know that? As the name implied, Caesar was born this way, a little
over 2000 years ago. It's likely the procedure is much much older, too. So
what timeframe are we talking about?

What we didn't know how to do 100 years ago was how to save mother and child
_once birth had begun_ and the baby's head had started to go into the canal
and got stuck. But humanity have known how to do caesarean birth for a very
long time (there are even cases of women doing it to themselves).

Also, from an evolutionary perspective it doesn't matter if the mother
survives birth; it only matters whether the baby lives. So it's at best
incorrect to phrase the problem this way:

> _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._

~~~
ptaipale
It is probably just a myth that Caesar was born this way.

At the time, the mother most likely couldn't survive a section, because the
resulting infections would kill anyone who had such surgery performed. And
Caesar's mother lived to old age.

~~~
gambiting
People have performed all sorts of surgeries for thousands of years, and while
yes, the percentage of them getting infected and resulting in death was
probably very high, it doesn't mean that every single surgery ended that way -
in the end, people have been amputating limbs or getting wounded on the
battlefield and surviving without any sterilization. So while it's rather
unlikely, it's possible that Caesar's mother survived the operation.

~~~
ptaipale
True, but deep wounds in the abdomen are much, much more difficult regarding
infections than e.g. limb amputation. Surviving that was very extremely
unlikely. Roman law said that the child must be cut out of a dead mother's
womb, to bury it separately, but by that time the woman was dead or dying.

As far as I could find, the earliest written source claiming Caesar was born
with C-section is from about 1000 years later.

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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.

~~~
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?

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Swizec
> one sentence per paragraph, a concerning recent BBC trend

3 of your 5 paragraphs are a single sentence.

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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.

