[bombcar]

I don't think mortality was 80% by 5 years, even 200 years ago.

But if you have ten kids, you won't be able to pay as much attention to each one as if you only had one, so even if you're perfect you'll have the kids doing more things without the parents knowing.

[waveBidder]

https://ourworldindata.org/child-mortality-big-problem-in-br... In the mid 1800's Germany it was ~50%, so every other. not as dire as gp, but definitely enough to change relationships.

[bombcar]

I'd be interested to see it broken down between literal infant mortality (those children who didn't survive birth, basically) and the rest.

From there, it seems the single biggest remaining factor is malaria.

(50% feels about right given reading accounts of "back then" and browsing graveyards)