Comment by blainm
2 days ago
Issues like these reflects an evolutionary blind spot: selective pressure drops off after reproductive age, allowing defects like prostate dysfunction to persist. It's the same reason late-onset neurological diseases remain prevalent.
Shouldn't kids with grandfathers have an evolutionary advantage?
They didn't say drops to zero, but the advantage is obviously more limited
If it wasn’t in the past, I imagine it will be in the future with how common two working parents is now. We want more kids but we are getting zero grandparent help
Two working parents have far below replacement numbers of children, so it would actually cause it to disappear…
The grandmother hypothesis https://en.wikipedia.org/wiki/Grandmother_hypothesis is reasonably well-established. The corresponding 'grandfather effect' has not really been demonstrated, as far as I know. https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2007...
Probably barely, and I think in some instances the opposite. You have to care for the elderly.
Grandparents used to be 40ish when their grandchildren were born.
when humans were still primarily subjected to natural selection the life expectancy likely wouldn't have allowed for many grandfathers.
You only have to live to your 40s to become a grandparent in natural conditions, and your chances of living to at least your 50s have always been pretty good conditional on living long enough to reproduce at all.
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Iirc, historically, if you made it to 10 years of age, most humans make it to 60
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The problem there is with your definition of grandfather. Currently, the age for a grandfather in developed countries is 55+. For most of humanity's history, if there were grandfathers, they would barely make it to 55 years of age.
No, plenty of people made it to that age in the past. Life expectancy was significantly depressed by infant mortality.
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We lucked out compared to other species, octopus develop dementia soon after breeding.
Yes, and there are spiders where the female eats the male after breeding. I bet their pr0n movies are a bit more interesting than ours.
Isn't that usually only in captivity where it can't escape?
Hmm. If we engineer late-life reproduction, that might create evolutionary pressure for healthy old age.
Hides long list of ethical problems with the concept
We missed the boat for that a few million years ago. If we're engineering anyway, we might as well engineer for healthy old age directly.
We just have to get the media to portray geriatric men as sexy, and we'll be well on our way to living to 200!
I know you're joking, but it's women that get the short end of the stick in media.
Men are (within reason) considered handsome in media even in old age. Wrinkles and gray hair can be seen as sexy (again, within reason), but only in men.
Women are discarded or relegated to sexless granny roles (except maybe for comedic purposes, where sexuality is the butt of a joke). Actresses are replaced by younger women because they are not sexy enough even when their male equivalents aren't (looking at you, Top Gun: Maverick).
I'm not saying there aren't exceptions in particular movies that deal with this topic; I'm talking about the general trend.
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The main problem is that evolution is just not a thing at our modern civilizational time scale.
And I don’t see any problems with late-life reproduction, assuming we can make it reliable and healthy. If anything, some countries desperately need it.
From my reading this is wrong in principle.
Evolution is really slow on average, but locally it moves quite quickly and probably explains the large variation between members of a species.
Add strong selective pressure to that high local speed and you can change a good part of the genotype within a couple of generations. See: animal husbandry. You can breed a new race of dog within 5-10 generations.
Ethics aside we could probably breed people who can sniff out Alzheimer's in less than 250 years.
Our current late reproduction style will very likely influence future generations health at older ages.
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Someone needs to remain alive to provide, protect and raise the kids.
Evolution is still a thing at relatively short time periods.
Icelanders are a well-studied population when it comes to genetics. Frequency of some traits meaningfully changed among them in last 100 years.
Source: this book: https://www.amazon.de/dp/0198821263?ref_=pe_109184651_110380...
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With our modern health systems we are pretty much a huge evolutionary blind spot ourselves. Many illnesses that would be filtered out because the carrier wouldn't survive, are now trivial. And on the journey hand we can screen for known illnesses.
I think we are already post evolutionary, or control it ourselves. Not a big issue either IMO, it's totally ok that this is happening.
We are definitely not post-evolutionary; the selection pressures have simply changed. Before industrialization the big two were starvation and infectious disease. Now? Well, it's anybody's guess decade to decade. Certainly sexual selection is still with us.
Dawkins suggested this might be viable (In an abstract; not politically practical) way in The Selfish Gene.
I read a pretty entertaining novel where that was one of the sub-plots.
The ethical problems were fun to read about! But would be significantly less fun to live through.
Name of the novel?
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We engineered it culturally already. Lots of people delaying childbirth until late 30s, early 40s today, often resorting to expensive treatments.
If we're ignoring ethics, then we don't need late-life reproduction.
Just kill all offspring if one of the parents die of some unwanted cause.
Allows people to still get kids in the optimal age, yet applying old-age selection pressure.
But the issue also causes male infertility, so that can’t be why it’s so prevalent. This is discussed in the article.
Male infertility after 60 is probably not very impactful from a selective point of view. For 300 000 years, almost nobody reached 60 anyway.
Before. Now people are delaying childbearing. Anedacta, past year one of my work colleagues had its first child, at 62.
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The article sort of mentions this in passing, but doesn't subject it to much rigor, and the (completely obvious?) counterargument is that by the time it causes male infertility, the affected have already reproduced.
what? so are you implying that prostate dysfunction makes you less wanted as a father if it presents itself in “the reproductive age”?
I read the comment as insinuating people stop taking care of themselves as much after children and develop unhealthy habits.
No. The grandparent comment was essentially saying that we, as a species, were not designed to live as long as we do. It’s only been <10 generations since medicine has been a thing. Cancers, dementia etc just weren’t a thing before because we evolved to live long enough to bring our children up to be self sufficient and reproduce, then our job is done. Like the rest of the animal world do.
Modern medicine has messed with this. We weren’t meant to “old”.
So widen the reproductive age (men only)
Why men only?
I think OP was alluding to the fact that risks of complications with pregnancy increases with age.
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Because you can't for women.