[Snargorf]

Not in 200 years.

What we're seeing now is a partial die-off.

Eventually, evolution will re-assert itself. The sub-populations who, for whatever reason, continue to grow in population will come to dominate the numbers, after the non-breeding groups die off.

E.g. in America, fertility is passing below replacement rates - on average. But the Amish population still doubles every 20 years. In 200 years, there will be hundreds of millions of Amish.

We could be looking at a world of Amish, Quiverfulls, poor tribalistic Africans, religious Muslims, and orthodox Jews. There will be very few left-liberals, the childfree movement will be gone (like the Shakers already are). Gays and other queer people may breed out of the gene pool if their modern freedom reduces the fertility of their genes.

Modernity may very well be self-defeating, because the future belongs to those who show up.

[speeder]

This is not coincidence.

The "traditional" policies and politics that many people claim that are "backward" or "evil", came from eras where the most important thing was breed soldiers like there is no tomorrow to fight against other tribes, then cities, then countries...

The point of allowing men having multiple wives, but not women with multiple husbands, prohibiting homosexual relationships, virgin marriage, encouragement of marriage, prohibition of adultery, prohibition of divorce, militarism, and a long string of other policies, are geared to one simple thing: make women "pop out" babies that can pick up weapons and fight (as soon as 12 years old if needed) the fastest as possible.

Those that follow these rules, will on long term always win, out of sheer numbers and resiliency.

[Aelinsaar]

Except that a few billion people can be exterminated by a few people if it comes to that, which is a very new situation.

[mrexroad]

Likewise, having a population of 1-2B also introduces the risk of scaling beyond the food production capabilities of the land. Obviously an overpopulated country can (and likely will) take from an underpopulated country, but modern weapons create a new dynamic if an invading force attempting to occupation farm land or capture grain stores is viewed as mortal threat.

[Aelinsaar]

That's exactly it, and it creates a situation in which relatively poor, very densely populated countries fight with each other for resources, rather than attempting to take from an underpopulated country armed to the teeth. I think we've seen a preview in the Middle East and North Africa, and gotten a hint of how Western nations are going to respond to the inevitable influx of refugees.

[Natales]

My biggest concern is the direct correlation to the reproductive rates and lower education in virtually every culture. More than specific concerns about particular religions or ethnic origins, I fear for a world where the uneducated rules.

[toasterlovin]

Then you should have lots of kids! And encourage your intelligent friends to do the same.

[ginko]

Well, it's not as if you can just choose to have kids.

[toasterlovin]

True in the technical sense that a person cannot just unilaterally decide to have children RIGHT NOW. But most people, over the course of their life, have the opportunity to have children. In the developed world, a huge portion of these people decide to have 0 or 1 child.

[sdfin]

Ha, that's the starting premise of Idiocracy http://www.imdb.com/title/tt0387808/

[88e282102ae2e5b]

Consider that many countries have made the transition from high birth rates and low literacy to the opposite. There's no reason to think the remaining ones will never change.

[Snargorf]

It's not in every culture, it's between cultures as well.

Africa adds 30 millions people every year. Pretty much everywhere outside of Africa is below replacement fertility.

In the 20th century, Africans were 10-15% of the world population; by the end of the 21st the could be >50%.

[int_19h]

The same problem was posited for China. Yet, as their quality of life improved, the problem had, essentially, resolved itself.

Similar trends have been observed elsewhere.

There's no reason to believe that Africa will be an exception from that rule.

[lmz]

Forgetting the One Child Policy, are we?

[int_19h]

You mean, the one that they have terminated last year because they now have an aging population problem?

https://www.theguardian.com/world/2015/oct/29/china-abandons...

[lmz]

You claimed:

> The same problem was posited for China. Yet, as their quality of life improved, the problem had, essentially, resolved itself.

It does not make sense to say the problem "resolved itself" when there was a 35 year period where the One Child Policy was in effect.

[Snargorf]

There are reasons.

China has a long history of advanced (for the time) civilization and a high-IQ population (~105). They were backward for just a few centuries because of a series of bad ideologies - isolationism, followed by communism. For most of history China was the highest-tech civilization on Earth. All they had to do to achieve demographic transition was get back to their historical norm.

Africa has no history of advanced civilization and a low-IQ population (~75). There's reason to think they'll sustain higher birthrates than everyone else, indefinitely. To achieve demographic transition they'll have to do something they've never done before.

[int_19h]

Given that IQ scores correlate pretty well with things like child nutrition, I'd wager that if you could actually go back and measure them for China back when they were "backward", you'd probably get similar results.

Not to mention that IQ is not an absolute metric - it's the median score of the entire population, and we're getting smarter as a whole, so 100 points today is "worth" more 100 years ago. Indeed, if you use the modern metrics, and apply them to the population of US - a well-developed industrialized country at the forefront of economic, scientific and technological advance - back in 1920, the average IQ would have been 80. So, if, as you claim, ~75 is such a low IQ that it would preclude these developments, then US should not exist as it is today.

[noobermin]

>Gays and other queer people may breed out of the gene pool if their modern freedom reduces the fertility of their genes.

By that logic gays shouldn't exist today.

[Aelinsaar]

For most of history whatever your sexuality, you married and had children. Period. You also did whatever else you did, and maybe you had a terrible marriage, but that probably wasn't unusual for straight people for most of history either.

[nikdaheratik]

Actually no, historically large percentages of the population (whatever their sexuality), especially the male population, did not marry as it was very expensive to start their own household. That's one reason why so many gifts were traditionally given for weddings. Though you do have a point WRT divorce being very uncommon.

[Aelinsaar]

That... seems wrong, but I don't know enough about this to dispute what you're saying. :|

[noobermin]

Let me expand my objection, homosexuality not only exists in humans but in many other animals, many of which do not have social stigma of homosexuality.

[Aelinsaar]

It may just be that in any system as complicated as sexual aim and expression, you will have variations like homosexuality.

[amargherio]

He's not saying that they shouldn't exist today, just that their genes will never make it back into the collective gene pool, stopping their traits and characteristics from ever propagating forward.

[cjslep]

But that's not how how genotypes and phenotypes work for recessive alleles. Homosexual genes will continue to live on and propagate in heterosexuals so long as they aren't eliminated by the gene therapy as seen in sci-fi horror/suspense Hollywood films.

It doesn't require a homosexual parent to have a homosexual kid.

[gwern]

'But that's not how how genotypes and phenotypes work for recessive alleles.'

Recessive alleles aren't immune to natural selection. It's just harder to purge them because they get exposed as phenotypes less often. As they become rarer and rarer (it'll manifest as a phenotype as the square of its frequency), selection weakens. Homosexuality, however, is common enough and the fitness penalty large enough that any recessives are exposed to a lot of selection, so it should be disappearing fast, but it isn't, which raises a lot of questions of what exactly causes homosexuality.

[noobermin]

Exactly at the heart of the problem. IANAB (I am a physicist though) and from what I understand, it is a question currently being researched. I mean, great example is if it is so easy, why is there homosexuality in the animal kingdom where they don't have social push for heterosexual mating?

[int_19h]

Yes, there is extensive research on this subject in ethology.

One hypothesis that seems to be fairly strong is that homosexuality is, essentially, just one manifestation of the broad altruism strategy.

Think about what makes altruism in general persist, despite it been seemingly harmful for its carriers long-term: they might not maximize the likelihood of survival of their own progeny, but in sacrificing that, they increase the likelihood of survival of progeny of people from the same family, tribe or larger community - which have a certain amount of shared genes. If you think of the natural selection game as fundamentally centered on the genes rather than their carriers ("selfish gene" etc), this strategy makes perfect sense - your altruism may result in a lot more people surviving and carrying genes shared with you, and down the line, the end result is that population in the future will be genetically more common with you than it has been otherwise - so your genes "win". If so, the tradeoff is in favor of altruism over selfishness, and altruism becomes a selected trait.

Now, homosexuality can be seen as an extreme example of that. Every homosexual pair that adopts children (and there are a lot!) is, essentially, forgoing spreading their genes directly, and spending the effort that would normally go into that on the genes of some other person. Now, in this day and age, children often get adopted across large distances; but historically, and obviously in nature, adoption would be from geographically and genetically close populations; so it's a form of altruism that can be favored by natural selection. If you unwind back even further, before family was a thing, any tribe members that don't have children of their own have more time to spend watching, feeding and protecting others' children.

Now, you might wonder, why homosexuality rather than asexuality, since the latter would produce the same result? Evolution, due to the mechanisms that drive it, generally takes the path of the least resistance at any given point, even if it results in a very long-winded trek long-term. And it's simpler, from an evolutionary perspective, to "neutralize" the sexual drive by changing its target, than it is to switch it off completely. On top of that, there are some benefits other than children to be derived from sexuality in social species - bonding and mutual assistance, facilitating communication (as e.g. bonobos often use sex) etc.

[A_COMPUTER]

Exclusive homosexuality analogous to human homosexual relationships is rare in nature. There are animals that are extremely promiscuous and have sex with anything else regardless of its sex, and there are animals that form homosexual relationships in the absence of enough sexual partners, and revert to heterosexual behavior when partners become available.

[nikdaheratik]

From a scientific standpoint, there's been alot of theory about an Aunt/Uncle advantage which is similar to a Grandparent advantage as far as it being able to help improve survival through the family of any genes responsible even if it is at the cost of an individual.

Of course, there's also the strong possibility that it isn't purely genetic but a mix of certain genes, which may be linked to other important traits, with a certain environment (possibly even in utero).

[toasterlovin]

The problem with the aunt/uncle theory is the math. A non-breeding sibling would have to enable their siblings to have two additional children (above and beyond the children they would have had anyway) for each child that the non-breeding sibling forgoes having themselves for the strategy to even hit break even, from a genetic point of view.

That's a steep hill to climb.

[Snargorf]

The hypothesis I put forth (implicitly) is that homosexual genes are still around because of the massive social pressure to have children and to never admit being gay.

Now that this pressure is gone, we could see a huge drop in these traits over the next few centuries.

[gwern]

I don't know how that is supposed to work. What sort of social pressure could possibly produce near-zero fitness impact when it makes you not want to have sex with women, in an environment where the men who do want to have sex with women are like 95% of the population and will happily put enormous efforts into doing that and taking your place? In addition, as I said, given the apparent fitness impact and frequent childlessness of gay men, we should be able to see homosexuality rates plummeting over the past century, but as far as I know, there's no evidence. (Plus the wild animal thing, yeah.) There's something stranger going on. The 'gay germ' hypothesis, as unpopular as it may be, at least adequately reconciles all of the observations.

[int_19h]

Your hypothesis assumes that, historically, all human societies had a massive social pressure against homosexuality. But it contradicts what we know about our history - there were numerous societies that treated it ambivalently (e.g. China, Japan, Native Americans) - and it didn't seem to produce any noticeable effect.

[toasterlovin]

But if the individuals who have the greatest expression or concentration of these genes are having children less frequently (because they are no longer pressured into having children by their relatives/community), then this will act as a siphon for those genes over many generations. That doesn't mean that they will completely disappear, but that these genes would become much less prevalent.

[toasterlovin]

I think homophobia is the reason why non-straight genes are present in the gene pool. It is a strategy for parents and siblings to make sure that their non-straight relatives reproduce despite their natural inclinations.

Just a disclaimer though: this is not at all a justification for homophobia, in the same way that the (mostly) male impulse to violence is not a justification for said violence.

[toasterlovin]

I was raised to always double down on an unpopular idea if I think there's something to it, so here goes:

From the point of view of genetic fitness, homosexuality is not adaptive. So you would think that the genes that contribute to homosexuality would be powerfully selected against, since the number of expected offspring from same sex intercourse is zero.

Yet gay people make up a sizable portion of the population, which is not at all what you would expect. Unless there is some mechanism by which homosexuals have historically had children despite their natural inclinations.

Given that some portion of anti-gay attitudes seem to be oriented toward getting them to "be more straight" (or whatever), it seems possible to me that homophobia (or at least a certain flavor of it) is an adaptation whose purpose is to get family members to pressure a gay person into having offspring, since they would have a genetic interest in those offspring.

But that is an argument about why a certain behavior might exist in humanity. It is not an argument that homophobia is okay or justified. It is not okay.

[nikdaheratik]

This is just myopic. The reason why many of those groups have more children is because in any agrarian household, more children = more free labor = more productivity. This can kick in at even a very young age.

In more urban centers, however, more children often means more cost for the family. It has next to nothing to do with religion, and in fact, most of the religious teachings that seem to encourage more fertility are probably just a case of putting the cart before the horse. Those teachings were emphasized because the households that listened to them already had a strong incentive to have more children.

The future, as far as anyone is able to predict, will still have much more urban, educated, and "liberal" people than not, even if those households have fewer children individually. And this will be true so long as we remain an urban rather than an agrarian society.

[collyw]

Religious nuts will rule. Not a good future.

[ggamecrazy]

A lot of us are all descendants of religious nuts. I'm not too worried.

[mafribe]

Our religious nut ancestors didn't have nuclear weapons.

[yongjik]

Yet they managed to raze cities just fine. If anything, modern religious nuts are quite tame compared to our ancestors.

[collyw]

Considering the amount of problems that religion causes at present, I am more skeptical.

[ittekimasu]

Digression: There is some reason to believe that "religion" has no real epistemological grounding outside the Abrahamic world.

[JabavuAdams]

Why do we assume that non-majority sexualities are genetic? As society relaxes wrt sexuality, we may see that many more people who do not identify as gay per se may openly display flexible sexuality.

E.g. saying you're left-handed is no big deal anymore. One day one's sexuality may be equally irrelevant.

[int_19h]

We don't assume it; we are still studying this extensively, and so far more evidence seems to be in favor of nature vs nurture.

If it were a matter of "relaxing", you'd expect that children raised in homosexual families would tend to be more open about flexible sexuality, and more would identify as gay, or at least as non-hetero - but that is not the case. The ratio of children becoming homosexual vs heterosexual is the same in both homosexual and heterosexual families, insofar as our studies can identify. At the same time, there have been some observed correlations between sexuality and specific genetic markers.

Really, the more interesting question at this point is whether it's mainly genetic, or mainly epigenetic.

[flashman]

You're extrapolating current trends as if they won't change in the future. Who is to say the Amish will continue to have as many children in the future? What if it turns out that reproduction is intrinsically tied to economic success, and the most successful groups of people always have declining birth rates?