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?