The Math of Fertility
If a society were to try to recover from a demographic cliff, what would the math be like? Well, one thing for sure is that it wouldn’t merely be a matter of going back to old trends. Old trends worked for old trends, they won’t work to correct new trends.
Introduction
Three things happened in the last couple of weeks that triggered the idea of this post in my brain. One of them was the announcement that the daughter of a friend of ours was engaged. A 32 year old daughter.
The second was that I heard some numbers about the demographic collapse in Japan. That when they first hit 100 million in population (on their way up) they had 7.5 workers per retired person. It is projected that when they hit it on the way down they will have… one.
The third was that I have been frantically working on a new story, which takes place in the near future; a future where the demographic collapse has caused wars and destruction, and the politicians have changed course and are encouraging everyone to have lots of babies.
Age at First
The thirty-two year old relates to the issue because, congratulations and all that, but she isn’t going to be doing too much helping as far as holding us back from the demographic cliff because… she is marrying far, far too late.
Let’s run some numbers. Kind of artificial numbers, but lets run them:
Let’s suppose that she is able to have a child every 18 months for the rest of her fertile life. So,
Married at 32
First child at 33.5
Second child at 35
Third child at 36.5
Fourth child at 38
Fifth child at 39.5
etc
Now, all that is assuming that she and her husband are fully dedicated to doing their bit to ending the demographic problem. Too bad I stopped the chart so soon, or they could have solved it all by themselves.
Except… I didn’t stop the chart too soon. I may have stopped the chart too late. The odds of a woman having five children if she starts at age 32 is vanishingly small. Leave aside all of the cultural issues, there are physical issues. At age 35 women’s fertility starts to undergo its own demographic cliff.
Now lets compare that to a woman who got married at 18:
Married at 18
First child at 19.5
Second child at 21
Third child at 22.5
Fourth child at 24
Fifth child at 25.5
Sixth child at 27
Eighth child at 28.5
Ninth child at 30
Tenth child at 31.5
So our eighteen year old could have ten children already before the thirty two year old even gets in bed with her husband!
Now, if anyone is wondering why I keep harping on about ‘married’, it is because that word typically applies to relationships that tend to successfully produce children. If you are in any other relationship that is producing children, just use your word here.
Total Numbers
Now, some people may be going a bit apoplectic at the idea of the five children of the 32 year old, let alone the ten or fifteen of the 18 year old. Surely, they are saying to their computer, it will be enough to have two or three!
Well, no. Let’s look at the problem. If Japan (and while they are at the forefront of this problem they are by no means the only ones in this disastrous situation) is going to go from one working person per retired person, to 7.5, they are going to have to increase the working class population by 6.5 people per.
Not only that, but they are going to have to do it by the time those people retire. And do so in such a way as to have people in the workforce.
And many of these goals are contradictory. But the end number is pretty clear: if they were to return to their previous numbers, they would need 7.5 people in the work force for every retired person, or 6.5 more than they have now.
And that is *per person*. Not *per woman*. Given those numbers the average childbearing woman will have to put 13 more people each into the the workforce. Not two, or three.
Infertile
Lest those numbers seem impossible, they get worse. We need to subract not only the women too young to help, and the women too old to help, but infertile women. Supposing that ten percent of women are infertile, that means that the remaining ninety percent have to take up the slack. That averages out to 14.4 children put into the work force by the remaining women.
Unwilling
Now let us look at the unwilling women. The women who, for one reason or another, are not willing to get married, have children, or have their share. Let us say that this group averages 2 children per woman. That would mean that the remaining women would have to produce sixteen children per woman.
You can see other charts on this but they all ignore many key factors. I may not be fully on point here, but my numbers are better than than any I have seen.
Let’s import them
Assuming that my readers think that the above is impossible, the first refuge that they might go to is to import the workforce. There are two problems with this. The longer you import people from another country into your country, the less it is your country. They come with their own values, and they don’t chuck them just because they are living with you.
The second problem is that that merely pushes the problem to another country. That, or those, other countries have to be producing enough children to both keep their population up, and to produce enough for you. So what might be 14 in your country becomes 16 in theirs.
Let’s Just Kill Them
The country of Iceland is not likely to be helping much with the Downs syndrome research, since they kill all of their Down’s syndrome children. The obvious trend to having to many old people is just to kill them.
But while that might help with the catastrophic elder care problem (if you can call murdering the people you would other wise have to care for ‘helping’), it doesn’t help with the fact that you are going to have millions of jobs going begging. And that people are going to keep getting old and they might get a bit antsy as they start to get close to the age where you plan on killing them.
Conclusion
The west, indeed the world, faces a coming demographic disaster. We don’t help ourselves cope with it by ignoring simple math. In order to even come close to reversing this decline, we will not be talking about two or three children per fertile woman, but eight or nine. And for that to happen we will have to undergo a massive cultural shift.
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Links
OK, so I totally was going to put a bunch of links here, and then forgot. Sigh. So, I’ll put them in now:
That Japan stat is eye-opening. I don't hold out much hope that things will turn around for the rich world in the next few decades, which is why I think the focus ought to be on softening the blow, and on finding ways for our families to best navigate a society in demographic tailspin.
>The third was that I have been frantically working on a new story, which takes place in the near future; a future where the demographic collapse has caused wars and destruction
At first blush, this seems implausible to me. But recently I was in a discussion about the economic history of slavery, and noted that slavery, or even lesser forms of oppression like serfdom, normally arise under conditions where labor is scarce and land is plentiful. Which is also the condition we're entering into! I don't expect slavery to formally return, but I do wonder what novel efforts will be made to regulate scarce prime-age labor in order to extract maximum productivity from it. The obvious one for most countries is emigration controls, but I also wonder if there will be more formal controls imposed. I can easily imagine countries drafting unemployed or underemployed layabouts into work gangs that fall somewhere in the spectrum between prison gangs, military conscription, and the WPA, while the old folks cheer that finally the young are learning the value of hard work.
Interesting numbers! Thanks!