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Cesarean Births Could Be Affecting Human Evolution, Study Says (bbc.com)
CanadianRealist writes: Larger babies delivered by cesarean section may be affecting human evolution. 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, [according to estimates from researchers at the University of Vienna in Austria.] Science Alert reports: "In the past, larger babies and mothers with narrow pelvis sizes might both have died in labour. Thanks to C-sections, that's now a lot less likely, but it also means that those 'at risk' genes from mothers with narrow pelvises are being carried into future generations. More detailed studies would be required to actually confirm the link between C-sections and evolution, as all we have now is a hypothesis based on the birth data." Agreed, more studies required part. Cesareans may simply be becoming more common with "too large" defined as cesarean seems like a better idea. It's reasonable to pose the question based simply on an understanding of evolution. Like it's reasonable to conjecture that length of human pregnancy is a compromise between further development in utero, and chance of mother and baby surviving the delivery.
Well 0.36/0.30 = 20% growth and it's only been ~2 generations, if you consider that most of the 3% in one generation will have kids with the other 97% in the next generation it seems unlikely to happen this fast. It's probable that it's more routine and we're more cautious today, so borderline cases get the surgery now where they wouldn't in the past.
Live today, because you never know what tomorrow brings
Previous generations and marriages gave birth to a more traditional (old-fashioned?) household, where the father was the only provider, and the mother stayed home to raise children, starting at a young age (late teens/early 20s). Compare and contrast this to what we see today as more of the average, where both adults perhaps go to school, start careers, spend time traveling the world, and then start considering marriage and a family in their late 20's/early 30's.
And this is not meant to sound mean or degrading, but we humans don't exactly shrink in size as we get older, thus making pregnancy and childbirth that much harder on a human body that may be leaning more towards the overweight or obese range. Perhaps mentally, the ideal age to become a parent is mid-30s due to maturity/wisdom/financial status/etc, but from a purely physical standpoint, childbirth is likely ideal at a much younger age, which a younger body may provide a bit more flexibility when it comes to childbirth.
It's actually a thing, Google "elective cesarean birth".
Women want to plan their expensive baby-party for a particular day, etc. You can't leave that to chance, not when you need to book the venue and the catering.
A lot of women also don't want to go through all that scary 'labor'' business or get their prize-winning vagina all stretched out.
No sig today...
There has only been one documented, (Poorly...), instance in History that Humanity physicality changed in a relatively short period of time- the 14th century. Starting in China, maybe, it spread throughout India, and then the Caucasus, into the Middle East and then north deep into the Scandinavian Countries. In two or three generations, half of the population of Europe died off due just to the Black Deaths. We don't know much about the other Civilizations.
One curious outcome can be seen in the clothing of the period. Europeans somehow got significantly taller over the following Century, after being stuck at Roman heights for over a thousand years. (Check out Suits Of Armor for a striking example.) Whether due to better nutrition; famines were common before the Plagues due to overpopulation and poor Farming practices, or whether there was some recessive Genetics going on due to past uncounted and unrecorded Plagues, is not now known. It's probably both; certainly poor nutrition can stunt inherited growth tendencies. And note that even without the Plagues, Infant Mortality bounced around 50%... Also note that this time was also the start of the "Little Ice Age", so Environment can't be ignored.
The European Countries in general, and the US in particular, have plateaued; 18 year old Males whose statistics have been gathered for centuries by those who like to play with War, have been tending to an average height of ~70 inches. In 1914, the average height of the Fresh Crop was ~67 inches.
But the growth in height is startling in some newly developing countries. In South Korea, it is now ~69 inches for Males. But in 1914, it was ~63 inches. Six inches is a pretty good jump, but South Korean women have jumped further- A gain of ~8 inches.
People have been growing bigger, but not at the same rates or at the same time. Generally, skeletal dimensions scale; taller women have wider pelvises. (Some populations in hellholes are actually getting shorter.):
http://www.npr.org/sections/goatsandsoda/2016/07/27/487391773/americans-are-shrinking-while-chinese-and-koreans-sprout-up
Cesarean births are still rare, and to draw any conclusion about general Evolution from their _recent_ trends is foolish. This is a damn stupid study; I suspect that there is an Agenda at work here. BTW, over the last few decades, the average US or Canadian baby has gotten slightly smaller:
http://www.wsj.com/articles/SB10001424052748704423204575017471267586344
Some breeds of dogs, bulldogs maybe?, HAVE to be born via C-section. The puppies can no longer fit the natural way.
Medical liability cases are increasing around the world, and the cost of insurance is driving many people from the profession. (See articles)
My wife wanted to give birth at home, it was both very difficult to organise and extremely costly.
All her friends said she was mad; plan the date with your Dr. for a C-section, fast, painless and no stress waiting for contractions to start.
It's as much a matter of convenience for both sides as a question of baby size IMHO.
http://www.medscape.com/viewar...
http://www.spiegel.de/internat...
The first hominid ancestors to us whose brains quickly developed much larger were avid seafood eaters. There are a number of telltale biological clues to this in our physiology, including the fact that our bodies don't manufacture DHA yet our brains and nervous systems require high levels of it. Also DHA is passed through the placenta to the fetus implying that the ancestors had an abundant supply of it in their diet.
...abortion could be affecting human evolution, too...
TRUMP 2016!!!
I don't think this is what he meant by "grab them by the pussy"
Not that I'm supporting Trump (he's more evil than Cthulhu, almost as bad as Hillary), but have you noticed how those 30ish women who accused him of sexual assault all went silent the moment the election was over? Shouldn't they be trying to bring him to justice? Maybe, just maybe, it was all staged false accusations as certain people like this kind of methods? See Assange, or what esr was tipped about.
The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.