Let’s say a magic solar flare renders 90% of normally fertile people permanently infertile.
What is likely to happen?
What would optimally happen?
I got the thread idea from
Utopia, an excellent British conspiracy drama
Enforced gamete harvesting.
The 10% would find themselves either very rich and powerful or enslaved. Suddenly there wouldn’t be any protest or objection to human cloning research.
There was a sci-fi short story on exactly this point - unfortunately, I can’t remember either the name or the author, as it’s been 30 years since I read it.
But, massive contraction of population and major social upheavals, particularly as the population ages and there is only a small incoming population to support the elderly.
The 10% of women who could have babies would essentially be baby-making slaves. Unfortunately. And most of us would probably sign up voluntarily, as long as we were treated decently - it’s not like we want to see the human race die out.
But I can’t see it going well at all.
global population, 7B.
Growth rate, 1.2%/yr.
average life expectancy, 70 yrs.
If life expectancy is 70 years, then every year, 1/70th of the earth’s population (100M people) die, and 1.012/70 of the earth’s population (101.2M people) are born.
If 90% of currently fertile people were suddenly rendered infertile, then if nothing else changed, the birth rate would drop to 10.1M babies per year, meaning the earth’s population would begin dropping by 89.9M per year, or about 1.3% per year. In other words, we’d have a fair bit of time to figure things out; it would be 50 years before the population were cut in half.
But of course things would change. Women who were still fertile would probably opt to have more babies, perhaps even putting them up for adoption. Maybe we’d even get together as a society and provide financial incentives for it. Women could have lucrative careers as child-bearers: make ten babies before menopause, and enjoy a comfortable retirement and free medical care to keep your uterus from falling out.
Would the next generation also be 90% infertile? If so, then that sort of scenario would have to continue. If not - if the next generation had normal fertility - then maybe the problem would self-correct over time without having to enact any special measures. There would be a temporary reduction in global population until the next, fully fertile generations reached child-bearing age, at which point the growth rate (expressed as % per year) would begin to climb back up to its pre-disaster levels.
I’m the first one to bring up The Handmaid’s Tale? Scariest darn book I’ve ever read, and it’s about exactly that.
I was thinking of that, also Children of Men, in which case it’s like 99.999999% (actually it’s 100% for a while).
But that was also reliant on the US being taken over by a Christian theocracy. Scary as fuck, but hopefully that’s not happening in the OP’s scenario (though it might).
Your maths is correct but in the medium term you’ll have a massive problem with the dependant to worker ratio until the preincident population dies off. Maybe people will work 'til the grave.
In the short term however, the lack of children to support would actually increase the amount of people in the workforce relative to dependants. This is why China has such a huge and unburned workforce, despite the one child policy creating an ageing population.
edit the generation born after the event will be fully fertile,
On one hand, there will be a big undercurrent of hopelessness and despair in the populace. Children give many people a sense of purpose and meaning. A sense that they are a part of something bigger than themselves.
But on the other, people will have more disposable incomes, a more carefree attitude, and spend more time doing things that they would otherwise not do. Like creative pursuits and personal development. Maybe they’d find harmony through their friendships and community involvement, rather than family.
Assuming that the first hand doesn’t contribute to a total breakdown of society, you will see poverty lessen considerably for a couple of decades. People will actually be able to save money. They will also take more chances and be less risk-averse, which could be both bad and good. But eventually, I think poverty would return as the age structure bottoms out. Social security would collapse. The streets would be full of poor old people, unable to eek out survival on their paltry savings, unable to care for their crippled bodies.
People will also stop marrying, except for the lucky couples that can produce. And maybe even they won’t, because there will be pressure for them to “share their genetic wealth”.
And you think our kids are overly entitled and spoiled now? Just think if we reduced their numbers by 90% and made them not only the special focus of their families, but of their towns and villages. “Little Emperor” indeed!
I think we might finally see major Social Security reform in the US. 
I’d sell my stock in Monsanto, as their pharma division would be selling lots less birthcontrol pills.
Your math is off. If 90% of the people in the world randomly became infertile then the “natural” birthrate would drop by 99% - because 90% of the fertile people would be coupled with infertile partners.
I remember the story, although like Northern Piper, I cannot recall who wrote it. As I recall, events played out pretty much as Anaamika speculates. Then, the next generation of children could only produce females. Kind of a downer ending.
5% of adult humanity (men) would suddenly become very very happy and would definitely abandon their former careers, whatever they were; they would become walking sperm banks.
5% of adult humanity (women) would find that their value had increased at least tenfold, so they would become baby machines, and grow rich in the process.
The divorce rate would increase as fertile/infertile marriages (which would be roughly 99% of the population) dissolved.
Young persons not yet of childbearing age (but, presumably, affected by the sterilizing event) would be mandatorily tested by the government, and their “fertile” or “infertile” status would be posted on government websites.
Adoptive children would now be in HUGE demand. Inventory would be completely cleaned out.
People would start bonking like bunnies.
That’s what I see happening. Having a baby would be taken completely out of fertile people’s hands, and the children would also be treated like an invaluable commodity. I can see the children being raised in crèches - you couldn’t leave raising the precious children to the vagaries of any random fertile person. Once you lose freedom of reproduction and the freedom to raise your children, what other freedoms start to get loosey-goosey?
The big question is what exactly female infertility means in this scenario. Is it just that 90% of women had their eggs zapped, or can they no longer carry a pregnancy to term? Obviously the former is a much easier problem to work with. Fertile women only have to undergo repeated rounds of egg harvesting (or is it possible to just harvest an entire ovary at once?); which as bad as it sounds is still better than being a brood mare. They could also have dozens more offspring than they could the natural way. The latter is Handmaid’s Tale territory, and Michelle Duggar becomes the role model for fertile women (though they’ll likely be “encouraged” to have children by as many different as possible). Hopefully assigned breeding get’s carried out artificially.
In a way, having children would become a luxury for the aristocracy, by adopting children, by buying the eggs and sperm off fertile donors or even by funding some sort of cloning process which is technically possible even now, let alone with the research money it would get in that situation. That could actually be a good motivator for some people to become successful.
The point I find interesting from the show Utopia, though, is that the “bad guys” do make a good case of explaining that no matter how terrible the worst case scenario you can imagine happening with all the infertility, it would still be only a small fraction of the horrors that overpopulation is causing and will continue to cause.
The 90% of women are 100% unable to carry a baby to term, even with someone else’s egg
Artificial wombs might be able to work though.
The 90% of men have unviable sperm.
Presumably this is one of the things that would change: fertile males and females would seek each other out. No fertile person would marry an infertile person without full awareness of that fact.
It’s questionable how much our personal freedoms would be curtailed. Maybe in some totalitarian countries (like China) they might mandate certain reproductive behaviors (e.g. ferts MUST marry other ferts, MUST have as many babies as possible, and MUST give some of them up for adoption), but I would guess that in the US we would just incentivize desirable reproductive behavior via a regulated free market. For the most part, ferts will probably want to marry other ferts anyway, so maybe that’s not something that would need to be enforced. A free market could provide financial incentives for reproduction. People already pay tens of thousands of dollars for surrogate pregnancy; maybe if fertility is that rare, the price would go up even more, and maybe it would be subsidized with a fat tax credit (or even just a large payment) from the government. If a football player can earn millions of dollars wrecking his body for sport, then under the OP’s hypothetical, it’s not out of the question for a fertile woman to earn very large amounts of money marketing her reproductive capacity.