Cesarean Births Could Be Affecting Human Evolution, Study Says (bbc.com) 277
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.
More likely medical practice, not evolution (Score:5, Interesting)
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.
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0.036/0.030 = 1.2
FTFY
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Re:More likely medical practice, not evolution (Score:5, Interesting)
I submitted the article. I completely agree with what you say. I did mention the idea that the definition of babies being "too large" might be changing due to cesarean becoming more routine. And I agree this seems to be happening too fast.
What I considered really interesting was the question: if cesarean became the normal method of delivery for an extended period of time (many generations) could humans end up at a point where natural birth was not possible?
Re: More likely medical practice, not evolution (Score:2, Funny)
Ah no. Sorry. Cuba in fact has more doctors. Cuba is a doctor factory - they literally export them all over the world. Greece is up there, but lags behind several countries.
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I heard (from the mother-in-law of a Greek) that it was a status thing.
Like having false teeth was at one time.
Alternate explanations (Score:2, Insightful)
Are there alternate explanations that also fit the trend? Many mothers are more careful about their health habits during pregnancy now than in the past, in large part due to a better understanding of what is helpful and harmful to the unborn child. Access to better prenatal care also certainly has improved the health of unborn children. Unhealthy babies often are smaller than healthy babies, and if there are fewer unhealthy babies now, then it follows that the average weight would increase. Although not hea
There's an obvious alternative explanation (Score:5, Informative)
Babies have been getting bigger for a long time.
This is well documented in medical literature:
- "These findings suggest that US and Canadian babies are getting bigger" https://www.ncbi.nlm.nih.gov/p... [nih.gov]
- "We conclude that Canadian infants are getting bigger" https://www.ncbi.nlm.nih.gov/p... [nih.gov]
- "Results presented in this study demonstrate that even when migratory effects are eliminated, a secular increase in birth weight is observed" https://www.ncbi.nlm.nih.gov/p... [nih.gov]
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rGBH hormone residues fed to make cows produce more milk being consumed by humans.
So glad I'm vegan.
Re:There's an obvious alternative explanation (Score:5, Funny)
Why? Are you scared of becoming a big baby?
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No, she is too emaciated to get pregnant.
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Lierre Keith makes a good point, that returning to natural grazing cows would be a huge benefit for the environment. Yes, I'm a methane fart denier. But her concern is with biodiversity, and all that tofu and grain is coming from stripping the land back to monocultures. I'm all for eating meat grown in a lab, if needed, but as humans, we have small digestive systems and big brains, and we didn't evolve that way eating veggies. But that's evolution for you, a lot of trial and error. Like this with the babies
Re:There's an obvious alternative explanation (Score:4, Interesting)
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.
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Thanks, interesting. I'm an avid meat and seafood eater, so I'm kinda vague with the term "meat". Another interesting point is the biomechanics of our lower leg and foot, which make us efficient runners -- not fast runners, just efficient -- which with the loss of hair, for sweating and cooling, makes us good for endurance running and running down large animals. Well, I wish, being at a desk all day. Anyway, it would be interesting how we actually got the initial start, whether it was on the savannah, or li
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Probably some combination of both.
If you can withstand often breathless and hyperbolic writing, I do recommend the book Born to Run, that discusses the idea that homo sapiens, in particular, are the supreme runners at long distance at moderate speeds, for the purposes of running down prey to death, which is a very effective hunting method in hot & dry climates when you have not developed good hunting weapons yet. I believe the conclusions are largely correct.
However, there is another tale that suggests
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The first hominid ancestors to us whose brains quickly developed much larger were avid seafood eaters.
They were also avid fruit eaters (we can't make vitamin C) and avid starchy vegetable eaters (unlike our closest relatives, we can digest starch).
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All this just reminds me how badly human beings are designed. Intelligent design my arse.
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There's an interesting TED Talk about our microbial colonies [youtube.com] by Rob Knight, He talks about the "clean" via cesarean issue you mention.
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rGBH hormone residues fed to make cows produce more milk being consumed by humans.
So glad I'm vegan.
Why?
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Because I don't consume growth hormone residues in my diet, so long as the fecal runoff water from factory farms doesn't get into the fields where my veggies grow.
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Because I don't consume growth hormone residues in my diet, so long as the fecal runoff water from factory farms doesn't get into the fields where my veggies grow.
So, totally off-topic then? We're talking about babies and birth. You're talking about perceived health benefits.
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If mothers consume dairy products with hormone residues their babies will be bigger, hence the increased need for C sections...
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If mothers consume dairy products with hormone residues their babies will be bigger, hence the increased need for C sections...
But you aren't either mother or baby. All you are doing is virtue-signalling.
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Having an oversized body as a consequence of a lifetime diet of growth-hormone-tainted food is a deformity. There are a lot of grotesque deformities now because of various adverse dietary and environmental factors which have been considered acceptable, usually for reasons of profit.
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If people stopped drinking milk many breeds of cow would go extinct. They have no natural habitat. It's a good job some people aren't vegan to help prevent the extinction of the poor domestic cow.
/ I'm being semi-facetious
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Q: What's the easiest way to tell if someone is a vegan?
A: Just wait, they'll tell you.
Tools and evolution (Score:2)
Man has discovered (created?) a new tool - and humans are taking advantage of it. Discovery or creation of tools have aligned with rapid growth of humans before.
Fire, Hammers, the Wheel, Machines, Beer, now this.
Therefore it stands to reason that bigger children will emerge through the use of this tool.
Babies and schedules (Score:2)
Newborns are so selfish that they don't have the *courtesy* to be born in business hours. Inconsiderate little brats.
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That's why approve of corporal punishment for newborns born outside business hours.
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Its everywhere (Score:2, Insightful)
Cesarean Births, Insulin and condoms may be affecting evolution...news at 11.
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Re:What about infertility? (Score:5, Funny)
Yes. A study done at the University of Dublin concluded that if your parents didn't have any children you probably won't either.
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The answer is yes. A lot of negative genes that would have resulted in a person not reaching reproductive age are being propagated whereas they might have died out if we were less advanced. Negative mutations in our genomes are not being removed like they once were.
It is theoretically possible that 200,000 years from now, humans would be completely genetically unviable without technology. (although technology will probably remove the bad mutations long before then in the real world).
Part of what the Naz
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I guess that explains the dramatic rise in the number of plain old fucking stupid people I've started encountering as my life goes on.
Seriously, there really seems to be MANY more of them around these days.
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I guess that explains the dramatic rise in the number of plain old fucking stupid people I've started encountering as my life goes on.
Seriously, there really seems to be MANY more of them around these days.
It's way too hard to win a Darwin Award these days.
Re:What about infertility? (Score:4, Informative)
Sorry but that is currently impossible to test because their are insufficient babies born from IVF that have actually reached adulthood to really analyse that.
I would note that Louise Brown has had two children conceived naturally and her sister Natalie has had four children all conceived naturally. For those ignorant of the facts Louise Brown was the first IVF child in the world and her sister was the fortieth born four years later.
Note that shows the low levels of IVF babies being born in the early years of the technology and why there are too few IVF born adults to really conduct any study into their fertility.
Is age a factor? (Score:4, Interesting)
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.
Re:Is age a factor? (Score:4, Interesting)
I've heard quite a few women look down on mothers who chose to have children at 18 or 19 - either for being considered feckless scroungers bleeding the social system dry or for not being feminist enough and having a full career first.
I think 18 is a very good age to have children. Straight after high school and it's not too late to go on to college at around 22ish. Admittedly you'd need a lot of family support, which is a good thing no matter what your age.
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I've heard quite a few women look down on mothers who chose to have children at 18 or 19 - either for being considered feckless scroungers bleeding the social system dry or for not being feminist enough and having a full career first.
Well, bleeding the social system can definitely have arguments against the idea of having children at an early age, but I think that particular factor has more to do with society looking down upon women who literally have many children for the sole purpose of increasing a welfare check. Unfortunately, society also has a hand in looking down upon young mothers for not "prioritizing" a career first. In the meantime, we wonder why so many kids grow up having more of a relationship with the daycare workers th
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Re:Is age a factor? (Score:5, Insightful)
Yes, because the incidence of that happening is almost insignificant, and using it to stigmatise all young mothers is simply wrong.
Not evolution (Score:2)
It's not evolution. Unless you consider operating theatres to be symbiotic. Take the surgery out, would the resulting deaths be considered devolution?
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Evolution is not linear and does not mean "improving". Evolution merely means a general change in gene frequencies over time. In terms of biology there is no such thing as "devolution". The increase in frequency of a trait that one might perceive as "negative" is still "evolution".
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It might be evolution, however it is not evolution by natural selection.
dogs did this (Score:5, Interesting)
Re:dogs did this (Score:4, Funny)
Some breeds of dogs, bulldogs maybe?, HAVE to be born via C-section. The puppies can no longer fit the natural way.
And now some women have to have children born via C-Section. I think this is proof that bestiality is on the rise.
Doctors and patients are more risk (& pain) av (Score:5, Interesting)
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... [medscape.com]
http://www.spiegel.de/internat... [spiegel.de]
De-evolution (Score:4, Insightful)
We have been de-evolving for a long time now. Lots and lots of "defective" people are living to reproduce who would have died without medical science (I am one of them). This ends up making the species genetically more poor each time.
Re:De-evolution (Score:5, Insightful)
Overspecialization can lead to extinction (Score:2)
I think the claim is that as the species becomes overspecialized toward reliance on medical technology, it faces a higher rate of extinction should a global catastrophe take medical technology away.
That assumes medical tech exists in a vacuum (Score:2)
That's highly debatable (Score:2)
Idiocracy was funny and all, but it's not science. And speaking of science, the human body is a machine, and we're capable of fully understanding it if we try. Maybe not in your lifetime or mine, but soon. Now, if we can just get the damn anti-science folks clamped down be
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Everything affects evolution (Score:5, Insightful)
Flawed conclusions (Score:3, Informative)
click bait (Score:3)
Genetic Engineering Solution (Score:2)
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Even today, studies have shown that hip to waist ratio is the number one factor in men apprising a woman of being attractive. (no I won't provide sources, people welcome to google it).
When showed a variety of women and asked to rank them, men would consistently rank women higher who had a larger hip to waist ratio. It turned out to be a larger factor than things like breast size preference, butt size, height preference, race, weight... for skinny girls and chubby girls the statistic that matters most for
Re:ummmm .... (Score:5, Interesting)
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
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Height change is easily attributable to dietary improvement. You could almost see it happening in Korea over the last few decades as they added meat to their diets. That's not an evolutionary change.
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I think you're right that no genotypic drift occurred. People were certainly small again from the industrial revolution through WW1.
The British army - admittedly scraping the bottom of the barrel by this point - had regiments of men around 5'2". One advantage - I guess they could dig a trench quicker...
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No it isn't because it isn't hereditary. If your children were to live on the same diet and have same health care as a Roman, they probably wouldn't reach 5ft tall. It's like if I cut off my thumb, my children wouldn't inherit that trait, they wouldn't be born without thumbs.
If people get taller because of better health and diet that is environmental change not evolutionary change.
Now, we can confuse this with epigenetics, it appears some genes that we already can be turned on and off and that can be pass
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Height change is definitely linked more to diet than evolution.
There is a well known example of evolution in humans though; the ability to digest lactose as an adult. Industrialisation and access to food has slowed the evolutionary change as there is less pressure for it now, but starting 12,000 years ago, the ability to drink the milk of animals as an adult was a strong evolutionary advantage- and spreading out of the middle east, it quickly spread into most parts of Europe and western Asia.
Nowadays with
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I've thought this through a few times. Same conclusion each time.
For humans, women are the selectors. Men are cheap. Women are the required and scarce resource, that is, willing women. Most any man is willing, with few exceptions.
Unfortunately, women today are using different criteria, the most important change being that they no longer have to put up with the man even for the duration of the pregnancy. They also need not even pretend to choose a man able to support them and their child(ren). Being 'will
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I love the misnomer in the title (Score:2)
"Evolving". Hah. Humans are effectively replicating but I would say that that process is quite far from evolving at this point in time.
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Define 'evolving'.
I bet you assume it's a positive, beneficial thing.
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Yeah, it's just all the rage to have Caesarians nowadays.
A mother just isn't "in" with the popular moms if she gave birth the outdated way.
Natural birth is just sooooo 2015.
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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.
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A lot of women also don't want to go through all that scary 'labor'' business
Who would?
Re:Pratchett and Baxter already predicted this (Score:4, Informative)
Who would want to go through surgery if they didn't have to, and then go through a year long period of recovery?
Apparently, at least 3%...that's just the number that were granted, not the number who requested it.
http://www.cosmopolitan.com/he... [cosmopolitan.com]
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I'm curious about the vagina stretching.
Is this a self-derived concept, they just assume that having a natural birth will permanently stretch their vagina?
Or is this a learned concept, literally "an old wives tale", with a natural birth mother complaining after having a baby that she noticed her vagina stretched after birth, affecting sex, and future mothers choosing cesarean birth to avoid it?
My personal experience is that it was generally more age dependent that childbirth dependent but not completely con
Re:Pratchett and Baxter already predicted this (Score:5, Funny)
You just came here to brag that you've sampled a statistically significant number of women.
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I'll just say that in my anecdotal case, where the doctor showed me the view up there, and I thought I'd never fit in that thing again...It all snapped back. Those things are AMAZING!
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The muscles of the vagina can weaken from many births which causes them to be unable to hold the vaginal wall properly. This in turn causes the vaginal wall to descend out of the body. There's a cosmetic surgery to correct it.
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Subjective evaluations aren't very useful in this area, and are the cause of much confusion.
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Re:Pratchett and Baxter already predicted this (Score:4, Insightful)
Err...I beg to differ.
I mean, most guys grow weary REALLY quickly of loose pussy and saggy tits.
Those two things are a big reason they divorce and 'upgrade' to a newer model after a few years.
Re:Pratchett and Baxter already predicted this (Score:4, Informative)
I'm curious about the vagina stretching.
Rule 34...
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You seem to suggest that it's not all that scary, not all that painful and not all that stressful. I encourage you to put a grapefruit up your ass and squeeze it out - and it still wouldn't be nowhere near the pain women feels during labor. Have you ever had a cramp? How long did it last? Try to prolong it for 6 hours every 5-10 minutes.
And why it's a bad thing women try to prevent their vaginas from being stretched out? Imagine that each time your partner gets pregnant someone cuts off one or two inches of
Re:Pratchett and Baxter already predicted this (Score:4, Informative)
My wife says that childbirth (4 kids, so it`s a relatively good sample) is nothing compared to either kidney stones or appendicitis. There, stop propagating that myth, it`s not that bad.
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And in the US at least, Obstetricians do schedule C Sections for their convenience.
It doesn't matter why. Cesarean delivery has consequences, and some of those may well be genetic manipulations.
And all this explains a multitude of things for me, while leaving several others unexplained, and exposing an inconvenient truth. Darn. I was hoping not, but so it is.
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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.
Heroism is alive and well.
Re: Pratchett and Baxter already predicted this (Score:4, Funny)
I agree. Unwashed lettuce can give you worms, and raw eggs can carry salmonella.
Re: Pratchett and Baxter already predicted this (Score:5, Funny)
Caesars carry risks.
Especially if you're a Gaul, or believe in Rome remaining a republic.
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Unless you're from this particular village in Gaul, in which case Caesars offer barely any risk.
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Caesars carry risks.
Et tu, Brute?
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TRUMP 2016!!!
I don't think this is what he meant by "grab them by the pussy"
Re:This is why we need Trump (Score:4, Interesting)
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.
Re: This is why we need Trump (Score:4, Funny)
Trump was in the white house a few weeks ago and he did shake Obama's hand. Coincidence? I think not.
Re: This is why we need Trump (Score:5, Insightful)
I hope Trump gets rid of vaccinations while he's in office. These diseases are here to help rid our gene pool of bad genes, yet we keep trying to save those less fit. It only hurts our species in the long run!
We need NATURAL selection.
Jenny McCarthy is right -- even if for the wrong reasons.
Good deal. At the next Ebola outbreak, hop on a jet over to that location and help bury the bodies, but you can't wear any protective gear. If you have 'superior' genes, you should be fine, right?
Jerkwad...
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Maybe your genes could've been tested better before you reached reproductive age.
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Indeed it could. Genes that make a male more likely to rape (aggression?) are not getting passed on like they would without abortion. Genes that make females more maternal (more likely to not want abortion) are going to be passed on more.
Abortion could be helping lead to a more "domesticated" humanity.