While I think these are fascinating theories that likely have some degree of truth...

What about the very simple theory that people have fewer kids when their opportunity cost to having kids rises?

I bet that explains most of the decline.

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You are making this waaaaaay too complicated. If you were to visit some of these poorer countries, you would immediately find that in most of them, the idea of parents providing a quarter century or more of full financial support for their children is a totally alien concept. Before WW2 in this country, it was still pretty common for kids to start working full time immediately upon completing primary school. They would continue to live with their parents, helping with the household expenses, until they got married in their teens and began the cycle for a new generation. Children in such societies are a huge financial boon for their parents. Not having them makes survival more difficult. In our society, parents are expected to shovel most of their life's earnings into the bottomless pit of child rearing and college educations in the hope that maybe their kids will one day help defray the cost of three bowls of gruel a day in a nursing home.

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I find this theory unconvincing. Rapid urbanization + decline in religion + lower status for large families are the main culprits in a falling TFR. The pill and modern feminism which denigrates motherhood are also to blame.

Everyone worried about declining fertility rates but how many of you have more than 2 children? Be the change you want to see in the world.

I have 3 kids, I'm highly educated and have a prestigious career. When I was pregnant with my third, people remarked how I was crazy to have a third and commented on how I would have a "big" family. I get looks when I walk into a store with my kids trailing behind me, like Mother Goose, or comments like "Wow, 3!". Rarely does someone comment on how wonderful it is to have 3 children and how it's a blessing. I tell people I wish I had started having children earlier so I could have had more. That always shocks them.

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Nov 17·edited Nov 17

While the relationship between falling fertility and wealth is well explored here, I am unconvinced by the Kings and Queens explanation.

It is completely lost when looking at overall TFR that there are actually at least two separate phenomena that have happened worldwide to lower fertility, and these likely have very different underlying causes. Phenomenon one is the traditionally understood "demographic transition" of average family size for women who become mothers falling to 2 to 3 children. This transition is still happening in Africa (in some places barely started), but pretty much done everywhere else is the world. The second, newer, phenomenon is the rise in women who never have children at all.

The first fertility transition started in the West as early as the eighteenth century (e.g., France) and was basically complete across the West (and in places like Japan) by the end of the baby boom. It is unclear to me whether desired family size actually changed over the centuries (this may well be linked to rising income and urbanization) or whether 2-3 (surviving to adulthood) kids was always the ideal average family size for women deep down, and now technology and culture had changed in a way to allow us to achieve it. Regardless, as Stephen Shaw has explored very well in his recent documentary project, Birthgap, this ideal has basically been constant across the West since the 70s. It is important to emphasize that average family size for women who have any children has held steady in developed countries for decades, even while overall fertility falls.

What is happening, instead, is a relentless and continuing rise in women who are childless. Birthgap summons good evidence that a large majority of childless women today wanted to have children, but simply don't find a committed partner in time (or at all). Shaw calls it "unplanned childlessness", and it is pretty global. Some middle income countries have an even worse childlessness problem today than places like the USA. It is a mating crisis leading to fertility collapse, and it seems to be closely linked to women spending more years in education (especially relative to men?). Rising wealth may be connected to the mating crisis story, but the Kings and Queens theory does not really fit here.

I'll note that there may be a third phenomenon happening today. Namely, a rising number of women genuinely not wanting to have children. Shaw couldn't find much evidence for this, but it may just take more time to emerge in the data. Certainly, there seems to be more expression of anti-natalism in culture and media in the last 10 years. It is possible that the "I don't want children" mantra is just cope for victims of the mating crisis or performative environmentalism that does not reflect real views or even a transient phase that kids grow out of by their thirties. It could also be a lasting and growing attitude that will further swell the ranks of the childless and push down fertility even more.

Finally, I think that, as the mating crisis deepens and average age of marriage rises further, we will see average family size for women with children erode while their desired family size holds steady at an average of 2 to 3 kids. Basically, more couples will hit the fertility wall before they can have their hoped-for second kid. I would be surprised if there is a growing number of people who specifically want to have an only child. I have only met one such person in my life, actually. All my friends with one kid wanted two, but started too late.

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In my mind, the simplest explanation for the u-curve is an economic one. I do agree with the initial assumption that wealth surpasses a certain threshold whereby people gain more opportunities (particularly women) and become more invested in other pursuits.

However, the decline at the upper levels is more straightforwardly explained in terms of the economic costs of raising children. Once you surpass a certain level of wealth, you have more means available for raising children and thus they become less of an opportunity cost than they did before. For instance, you can rely on just one salary or hire a nanny part time or whatever. You have options available that a middle income family doesn't have access to.

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“but humans can’t choose the sex of their babies.”

Yes they can. Infanticide is historically common.

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There is a simpler explanation, which passes Occam's Razor test. Fertility is related to women's college education. In poorer third world countries, women do not go to college. They get married at a young age and have bigger families. In wealthier third world countries, women go to college. They spend their most fertile years in colleges of higher education and advancing their professional careers. Once the higher educated women realize that their biological clock is ticking loudest, they only have time to make one or two children.

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Nov 17·edited Nov 17

No amount of "encouragement" is gonna get Whites and Asians to have more kids. It's an economics issue -- they know that 50% of their income is going toward black & brown families they have unwillingly adopted. Thus, they have fewer resources to have and support their own children. Take away blackies & brownies from the earth, and you'll see the White and Asian birthrates go up rapidly.

Worldwide negative eugenics is needed, and that can be found here:

https://childfreebc.com/candidates/ - private, voluntary, strongly EUGENIC. Donate & share. Save the West.

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i am so confused by some assumptions....low fertility is bad ? why ? can our country maintain itself with a population of 15,000,000 instead of 350,000,000 ? why is growth (increase in number) of any sort assumed to be ideal ? i think modern society will do just fine as the number of children women gestate decreases.

there are individuals who believe society will develop solutions to reproduction, if more humans are required for a "healthy" society. it may not be a "brave new world" but what happens when reproduction becomes a technological process independent of human bodies ? will fertility matter then ?

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> This means we have to imagine something in our evolutionary programming that says “limit fertility when you are close to becoming a king, but be fruitful when you actually become a king.”

Couldn't polygamy explain this? For peasants, optimal reproductive strategy is for a monogamous couple to have a dozen kids together. For royalty, optimal reproductive strategy is for the King and Queen to have two or so kids that they invest as much as possible into while the King has a dozen concubines on the side pumping out kids.

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My personal speculation is that the fertility crisis is essentially a game theory problem.

Say you’re a woman in a developing country, whose economy is growing year-after-year. You’re optimistic about your personal prospects and want to escape poverty, so you pursue education instead of early marriage to increase your income potential.

If you’re the only woman in your community to do so, this is a no-brainer. You get an income boost and you have your community/parents to help you with childcare while you and your husband work.

Now let’s imagine the same scenario, but in a society where more and more women are pursuing education. Not only do you not have a community to help with child-rearing, since everyone is at school or work, the relative costs of living are increased such that an education is required to provide the same relative standard of living (and status) as it was before any women in your community were educated.

An indicative phenomenon of this dilemma is the HCOL couple where the woman reluctantly quits her job in order to raise the kids, because childcare would cost more than she earns.

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White & Asian elderly have retirement savings, pensions, 401Ks, Roth IRAs, and adult children who help take care of them. blacks & hispanic elderly have none of these -- we paid for them during their younger years, and we'll pay for them until they die... bc someone has to pay for their Democrat votes.

Feminism, more education, etc are contributing factors for lower White & Asian fertility, yes. But economics influences behavior, whether people realize it or not. Raise the prices of a Snickers bar by 1 cent, and you will sell fewer Snickers bars. It requires an understanding of Microeconomics to grasp this, but it's an indisputable concept.

Your ad hominem attacks are unwarranted, and reveal your lack of any real argument.

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What about the link between belief in Abrahamic religion and income in high-income societies? Generally speaking, even in the oil-rich Gulf countries, the more one makes, the less religious one gets. The Abrahamic religions all have heavily promoted having as many children as possible, so if high-income people don't have religious faith, they don't feel a purpose to have children.

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There is a simple theory that explains the fall of fertility better than status theory: people don't like raising kids. So when they can choose how many kids to have, they choose few. To be able to choose you need to have some human capital to use methods to control fertility.

Middle income countries are countries where the population is accumulating human capital fast so the population is transitioning to the capacity of control fertility. After median incomes are above 20,000 dollars, then most people can control fertility.

This theory can help to explain the population collapses in Ancient Greece and Rome BTW (I don't think it's possible to use a single dimensional variable to compare their living standards with modern ones):


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Using GDP without marrying it with income distribution seems like a suboptimal way to measure individual behaviors by class.

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Actually, Kings and Queens have more kids (within their own societies). And probably true historically too - Genghis Khan impregnated half of Eurasia/had a sizeable harem. The lowest Mongol warriors most certainly did not.

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