Imagine that all men in the world became infertile right now. (This would apply also to all new born boys for as long as no cure was found.)

How much time would humanity have to find a cure (or lift the curse, if the reason is magical)? Think of using already existing frozen embryos (no new ones could be created) as part of the strategy.

What risk-minimizing strategy should be employed if the target is the survival of the human race (male and female)?


To clarify the question:

Currently there is a limited number of frozen embryos in storage world wide. Some of them could brought to term in x years. After another x years we still would have women who would be able to bring some of the embryos to term. This might considerably increase the timespan that is available to humanity to lift the curse.

But what is the strategy to minimise the risk if something goes wrong? All at once would give us only one generation. Only 2-3 children would give us no margin of if something goes wrong. How long do we choose the time for bringing new embryos to term?

  • 1
    $\begingroup$ What do you mean by risk minimizing? What specific risk? Risk of extinction? $\endgroup$
    – jedmeyer
    Aug 31, 2018 at 16:02
  • $\begingroup$ yes: The risk that the human race won't survive $\endgroup$
    – user54884
    Aug 31, 2018 at 16:03
  • 2
    $\begingroup$ Can you tell us more about how or why the males are infertile? Science is pretty good at doing a lot of things, and the mechanism that causes infertility could interfere with some of the solutions. $\endgroup$
    – Mathaddict
    Aug 31, 2018 at 16:34
  • 1
    $\begingroup$ VTC.. interesting question, but duplicate.. there's a very appreciated topic about this worldbuilding.stackexchange.com/questions/44159/… $\endgroup$
    – Goodies
    Aug 12, 2022 at 11:57
  • $\begingroup$ How is the obvious answer not "until all the males are dead"? $\endgroup$
    – John
    Aug 12, 2022 at 13:37

2 Answers 2


Assuming your infertility method completely wipes out our current birth enhancement tech, we're not too far from being able to clone a human if we need too. The current mechanism for successful reproductive cloning:

In reproductive cloning, researchers remove a mature somatic cell, such as a skin cell, from an animal that they wish to copy. They then transfer the DNA of the donor animal's somatic cell into an egg cell, or oocyte, that has had its own DNA-containing nucleus removed.

Would technically allow us to wipe out men from our need from reproduction. So we would be a race of artificially induced clones!

How long until we had to do this? Not long.

If it took us 8 years to effectively develop cloning or artificial reproduction, we would have a huge chunk of a generation just missing.

In the future, this could easily result in a labor shortage.

So what's our upper limit? The older that women become, the higher the chance they end their fertility, which is called menopause. At the absolute worst, we have 45-50 years before the youngest children become no longer viable to have kids of their own (ignoring the massive labor shortage that we would inevitably experience). Taking longer than this would likely doom our species.

Risk management wise: there isn't much you can do when your species can no longer reproduce naturally. Cloning is expensive, but you can bet that biotech companies will flock to reproductive research. At worst, you want to ensure the stability of society as long as possible, so that your scientists can discover a cure before a species-wide existential mass panic. Best is to keep your populace informed, promising treatment and reproductive opportunities to all who request it (once/if it's available).

  • 1
    $\begingroup$ Okay, I think I must improve my question: We have hundred thousand of frozen embryos some of them could be implanted in 30 years. After another 30 years we could do it again and again. The number of embryos is limited. What is the best strategy to prolong the existence of the human race (during which the curse might be lifted). $\endgroup$
    – user54884
    Aug 31, 2018 at 16:08
  • $\begingroup$ You should add that information to your question. $\endgroup$
    – jedmeyer
    Aug 31, 2018 at 16:12

An option along a similar line to @jedmeyer's would be test-tube babies. Take the genetic material from one egg and inject it into another, basically test-tube babies. There's plenty of reading on the subject.

The obvious biggest risk factors with any of this is going to be war, for various obvious reasons. In fact, there are potentially many risks, far too numerous to mention here.

  • $\begingroup$ Ha, I'm a test-tube baby! I didn't know it worked with just genetic material! That would work if the father still had sexual genetic material, which I guess depends on the method of infertility. $\endgroup$
    – jedmeyer
    Aug 31, 2018 at 16:21