But the 18th century is far enough for us that we already forgot this.
Edit: found it - its called the variability hypothesis https://en.wikipedia.org/wiki/Variability_hypothesis
I think this indicates this idea is polarizing and that the people who found the statement outrageous downfloated while those who were able to engage with it in a critical manner posted some interesting content. I think that's a very interesting signal about this kind of idea that it's so polarizing. At least in this small sample size of hacker news readers. who knows how that compares to the general or larger or different population tho?
Had the difference been caused by variance, you would find slightly more men at some places. You would not find "only men" nor "almost all men" as your comment claims.
And also, the world was build by plenty of completely sane people of both genders. Majority of it, actually.
Low tech and behind-time rural villages are big on gender roles. But child rasing is only one of things women do and did. They used to spend awful lot of time by producing things - making threads out of flax (flower) or wool, then material then sewing. They tended animals too, made candles and so on and so forth. Kids contributed from early age.
Theory that limits female contribution to childcare is likely projecting 1950 middle class roles onto past. Just mere ability to sustain adult and teenage humans who are not contributing to actual essentials production assumes basically wealth. It was not even affordable for most population.