The hypothetical is that some disease sterilizes all human males. Without exception, and I realize that’s virtually impossible, but don’t fight the hypothetical. Say it’s alien space bats that do it, if that makes you happier. Anyway, no one can find a cure or immunization for the sterility, so humanity is reduced to using whatever sperm banks have on hand.
The question is, how long could civilization last in this situation?
Some thoughts: only one sperm actually fertilizes an egg, but somewhere (likely here on the SDMB) I read that it actually takes a few million or so sperm to dig into an egg in order for that one sperm to do the fertilization. If that’s true, the available sperm can’t be spread out too thinly.
Civilization needs a certain minimum number of people to make it run, say half a billion or so, so the reproduction rate can’t be reduced too far.
The thing is, I have no idea how much stock sperm banks keep on hand. I suspect not a lot. Also, I’m not sure how many countries even have sperm banks. I suspect they don’t exist in much of the world, but could easily be wrong on that.
In your hypothetical is it only the current living males who are sterile, or will all future males being conceived (from, say, sperm banks) also be sterile?
If it were a high priority (which it would be), we could develop the technology for women to reproduce without men, within the lifespan of those currently alive. So civilization could continue indefinitely. The biggest risk would be that the discovery of the sterility would be the catalyst for a global nuclear war, as various nations blamed The Others for causing the sterility, or thought that The Others had a cure that they were withholding, or decided that since The End is Nigh anyway, there’s nothing left to lose.
Under lab conditions, it is possible to have female-only reproduction. For example Mouse Created From All-Female DNA. If all men became sterile, I’d imagine that there would be a lot of work directed at finding similar techniques for humans.
Since we haven’t developed that technology yet, there’s a possibility that it’s impossible for some reason. OK, that’s also not too likely, but lets assume it for this question.
Also assume that nuclear war does not break out, or at least is limited to not being a major problem for humanity going forward.
Just in really round numbers, the world has seen something like 7 or 8 billion successful impregnations in the last 80 or so years. There’s no way that the world’s sperm banks (and medical experts necessary to effect the procedure) could match that sort of volume. Not even close. For most everyone, there’d be no more children, and populations would start to decline rapidly, and what we call “civilization” would grind to a halt over the next few decades.
I don’t know that I agree with the number given, but if all that’s left is a “village”, I don’t think that really counts for the OP’s purposes. Just one “village” is probably going to see it’s lifestyle regress to something more like 18th century living. They wouldn’t be able to produce more automobiles, or refrigerators, or paint. Virtually no additional movies or books would be released. I’d be impressed if they could keep a steady supply of electricity for themselves. Research and development efforts in a whole swath of fields would come to a halt. Tasks like training new doctors would be a real challenge, etc.
There are hundreds of thousands, possibly millions, of already-fertilized frozen embryos in deep freezes in the US alone, plus more in Western Europe, Japan, etc.
There were something like 140 million live births last year. “hundreds of thousands” of frozen embryos are barely going to put a dent in replacing those, even if all the necessary technicians, doctors, facilities, (and willing patients!) were available to perform the procedures.
There were 3.8 million live births in the U.S., against the hundreds of thousands to low millions of frozen embryos here. If you want a kid, and the choice is a frozen embryo or no kid, then you’ll find willing patients.
There are of course far fewer, if any, frozen embryos in the high-birth-rate countries of sub-Saharan Africa, etc.; I do not know how many may exist in Canada, Australia, Japan, the UK, etc.
I don’t recognize that name. But the question is more in the line of research for a fictional story. Chances are I’ll never write it, but I like to work out the details of the background in my head.
I just pulled a number out of my nether orifice. Perhaps the number is only 100 million or even less. Certainly lots more than a million, though. If you think half a billion is too high, go with 100 million.
How many fertilizations per year do we need to maintain a population of 100 mIllion? Do we have enough medical people to do that many IVFs? Can the process be streamlined to do more with fewer people?
Yes, those could be used. I expect most, if not all, sperm banks, fertility clinics, and any other potentially useful facilities to be nationalized in such an emergency and any rights anyone had to the contents thereof to be taken away.
Just try not to make it too much like “Children of Men.”
Because apart from your premise requiring that it specifically be the males that are sterile (why does it matter? Does it change your premise much if it’s just that for “reasons” people can’t reproduce anymore?) that’s basically the world “Children of Men” is set in. It’s been 20 years since the last infant was born, things have gone to shit, and then one day…
Even if alternate methods of conception were cheap and easy (e.g. at home kits sold at 7-11), it would likely mean that conception became more of a choice. Accidental pregnancy would not be an issue. I suspect that many people would not really try all that hard to get pregnant. Even when everything is working normally it can take many tries to get pregnant. I don’t know how dedicated people would be if they had to keep buying kits or getting procedures done to get pregnant. Some people do endless IVF, but I don’t think most people want kids that badly.
I also don’t know how dedicated people would be to the cause of carrying on the human race. If society is collapsing because of the resulting population decline, would people want to bring a baby into that world? Even now, people have concerns about bring kids into the world we have today with all the social unrest and climate issues. I would think there would be even more worries in a world in decline.
We’ve been able to clone mammals since the 1980’s. So we have the technology available to create new humans even apart from ordinary reproduction or using frozen sperm (which will of course run out eventually). It would be an existential crisis, and we’d have twenty years to ramp up facilities for artificial insemination/cloning before the working-age population started to suffer. I’m pretty sure any high-tech developed country could manage this.
IVF treatment seems like a reasonable approximation of whatever no-sperm-necessary wizardry we might invent to keep the human race going once the sperm banks and egg freezers are drained. WebMD describes the process like this:
The article mentions success rates of ~20-40%, but that’s probably driven by the self-selecting group of women who are already having difficulty getting pregnant. If we started doing it for all sorts of young, healthy women, I suspect you’d get better results.
https://www.pennmedicine.org/updates/blogs/fertility-blog/2018/march/ivf-by-the-numbers says there were 61,740 IVF births in 2012 (in the US), roughly 1-2% of all births. To keep the population going at the present level, we’d need to train about 50-100 times as many doctors and lab technicians in the new process than we have IVF-performing fertility docs and support staff today. I don’t think we have the med school capacity / internship opportunities / whatever to do that, and we can only really start after we’ve ironed out the kinks in the new cloning / sperm-free process, a fairly heavy R&D lift, I think, that could span years or decades. I imagine it’d be something like the Apollo program or the Manhattan Project in terms of national urgency, but still seems tough to pull off.
And that’s, of course, focusing on the US. Other modern democracies might be able to roughly approximate our effort, but like Aspidistra said, “The developing world would be screwed”, as in, essentially cease to exist in a few decades.
I suspect America would be the most populous nation in the world by 2100 at the latest.