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The heritability of fertility makes world population stabilization unlikely

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Re: The heritability of fertility makes world population stabilization unlikely

#31

Post by bhouston »

The main factors currently in determining family size is not genetically heritable, but cultural. Culture appears to be heritable but that is just because culture tends to be passed down.

Culture can change fast in either way, towards more children or less.

This does not mean we will be stable but rather culture matters.

For example soon as a member leaves a conservative religion stream and shifts to a more liberal streams their fertility instantly drops in one generation. Israel's government even models this in their demographics projects as the flow between religious streams of Judaism is the biggest fertility modifier in that country.

This does means in part conservatives will inherit the earth because liberal culture right now cause smaller families but this is culture. I think liberals have to fix this.

Also if a women gets an education her fertility drops and the more education the lower the fertility. This means uneducated women (for whatever reason, religious or other) will inherit the earth. If educated women tend to be those with more genetic talents, and in aggregate this may be the case, then this is quite a problematic trend long term.

I think the trends to who has fertility and who doesn't isn't great and should be a real topic of conversation. As a society currently we do not deal with this head on.

Re: The heritability of fertility makes world population stabilization unlikely

#32

Post by mehrdadn »

bad_user wrote: post #14

All of my grandparents come from big families. My grandmother on my father's side comes from a family of 12 children. Yet my grandmother only had 4 children and my father only 2, and now I only have 1. This is an anecdote, but I don't think heritabiliy has anything to do with it. Large families simply happen due to poverty. When poor, you want more children because there's strength in numbers. Plus the women are stay…

There's also climate change https://qz.com/1590642/these-millennials-are-going-on-birth-...

Re: The heritability of fertility makes world population stabilization unlikely

#33

Post by mynameishere »

benj111 wrote: post #20
andybak wrote: post #5

Could someone with more time than me summarize how they reached the conclusion that fertility was heritable? It seems very counter-intuitive unless I'm misunderstanding the precise meaning of "heritable" that enables them to draw this conclusion.

"how they reached the conclusion that fertility was heritable?" Isnt it obviously true? If you don't breed you don't pass on your non breeding genes, if you do breed.... Living organisms are literally breeding machines, that's all they really do. Natural selection favours those who do it better.

It's beyond obvious. Strange that people are arguing against it.

And, going one further, in the past people had children as a matter of rote. Now, it has to be a deliberate, overcoming the obstacle of modernity, in a sense. In the same way smallpox had a habit of reducing the population's potential, so too (by a different mechanism) does education, birth control, abortion, etc. A subset of the population will effectively become immune to those things.

Re: The heritability of fertility makes world population stabilization unlikely

#34

Post by 0xd171 »

adrianN wrote: post #25

Catastrophic climate change makes it very unlikely that people in the future will breed with similar success as in the past. Especially poor areas that today show high fertility will be hit hardest by changes over the next twenty to fifty years.

Isn't your reasoning backwards?

We know that improvements in living conditions lead to reduced fertility. And climate change will worsen living conditions, not improve them. So if areas with poor living conditions have high fertility now, why would even worse conditions (due to climate change) reduce their fertility? Sure, the outcomes and quality of life of the children will be even worse than it is but I can't see how that will impact rates of reproduction.

Re: The heritability of fertility makes world population stabilization unlikely

#35

Post by barrkel »

Al-Khwarizmi wrote: post #7

If this is true, then how do they explain population stabilization in, e.g., Europe, and other developed areas? Why shouldn't what worked for Europe work for the rest of the world?

If the majority of people are only now limiting their fertility due to reduced infant mortality, availability of contraception, and both parents working making childcare more expensive, and increased cost of education and housing (itself often a proxy for education), then genetic or cultural traits that promote fertility even in the face of these trends will only now come to the fore.

Re: The heritability of fertility makes world population stabilization unlikely

#36

Post by mxfh »

car12 wrote: post #29
acqq wrote: post #26

Earlier quoted context omitted.

I suspect that “Southeast Asian” women observed had different religion than those where “fertility pattern of their parents” is preserved. Not all religions have the same effect on the outcomes, ignoring that in the studies is misleading.

What it is pussyfooting around is that there is not that drastic of a drop in fertility rates of muslims. I guess it shouldn't be hard to conceive where Islamic parties start having a major voice in elections because of demographics.

By numbers, global fertility/population trends and religion are not a "muslim" one, that's a made up western "identity" problem. If anything it's catholic to evangelical sectionism, if you look at Western Africa.

Overall religion is secondary at best, but economically weak tribal/familiy social nucleus cultures vs established nation states that provide reliable social safety not just for relatives.

"It's the Economy, stupid", look at fertility rates of Saudi Arabi, Iran, UAE Poland vs Nigeria.

Re: The heritability of fertility makes world population stabilization unlikely

#37

Post by raxxorrax »

mxfh wrote: post #11
andybak wrote: post #5

Could someone with more time than me summarize how they reached the conclusion that fertility was heritable? It seems very counter-intuitive unless I'm misunderstanding the precise meaning of "heritable" that enables them to draw this conclusion.

So far the consesus was that migrants from traditonally child rich societies, acclimated already a generation later at local lower levels if prosperitiy and education level was reached as well. So it's the economy and social stability through the state that replaces children as the only "pension and care" provider for retirement. FRANCE: "We show a convergence towards French standards that differs across groups of or…

If you want to know anything about future demographics, just look at a school. Should not be that hard honestly.

So if first generation migrants have a greater fertility, it can indeed affect demographics to a large degree. Because you need exactly one generation to do so. Obviously.

And it should also be obvious that lower fertility stems from multiple factors. Birth control is one, modern work structure is the other. I am certain there are more.

Re: The heritability of fertility makes world population stabilization unlikely

#38

Post by qualmer »

pas wrote: post #28
barry-cotter wrote: post #22

Earlier quoted context omitted.

If a trait is not strongly selected for but variation exists it will be maintained in the population. See height, hair colour, propensity to gain weight, etc. Then you change the environment so that the trait is under strong selection. The people living in Scandinavia 3,000 years ago couldn’t digest lactose. Now ethnic Scandinavians who are lactose intolerant are basically nonexistent. It’s at above 99% homozygotes.…

> It’s at above 99% homozygotes. Meanin 99% of people who have this allele (trait) have two set of the corresponding gene/genes. Okay, but is lactose tolerance a dominant allele?

Yes, lactose tolerance means you have functioning enzyme. That makes it a dominant allele.

Re: The heritability of fertility makes world population stabilization unlikely

#39

Post by adrianN »

0xd171 wrote: post #34
adrianN wrote: post #25

Catastrophic climate change makes it very unlikely that people in the future will breed with similar success as in the past. Especially poor areas that today show high fertility will be hit hardest by changes over the next twenty to fifty years.

Isn't your reasoning backwards? We know that improvements in living conditions lead to reduced fertility. And climate change will worsen living conditions, not improve them. So if areas with poor living conditions have high fertility now, why would even worse conditions (due to climate change) reduce their fertility? Sure, the outcomes and quality of life of the children will be even worse than it is but I can't see…

Sufficiently bad conditions lead to children starving and women not surviving labor.

Re: The heritability of fertility makes world population stabilization unlikely

#40

Post by car12 »

mxfh wrote: post #36
car12 wrote: post #29

Earlier quoted context omitted.

What it is pussyfooting around is that there is not that drastic of a drop in fertility rates of muslims. I guess it shouldn't be hard to conceive where Islamic parties start having a major voice in elections because of demographics.

By numbers, global fertility/population trends and religion are not a "muslim" one, that's a made up western "identity" problem. If anything it's catholic to evangelical sectionism, if you look at Western Africa. Overall religion is secondary at best, but economically weak tribal/familiy social nucleus cultures vs established nation states that provide reliable social safety not just for relatives. "It's the Economy,…

The post that I was replying to was talking exactly about fertility rates of second, third and beyond generation immigrants in Netherlands.

And what was found is that females from south-east Asia had a big drop in fertility whereas Turks continued to have large families, comparatively.

So, no, the above research specifically disproves your argument.

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