After WWII, when millions of men aged 18-40ish from countries across the globe had been killed (or disabled to the point where they couldn't work/care for a family), leaving hundreds of thousands of unsupported or single women and widows, how was that handled? Was being a single woman just "the thing" for awhile?
How did countries like China and the USSR deal with having such a heavy blow dealt to their prime workforce?
/u/koldovstoretz recently answered "Did countries other than the USA experience a baby boom after world war 2?" with regards to the USSR, which might be of interest for you, and I'd also point here for a slightly broader look at Soviet natalist policies.