> While "having lots of children leads to physically demanding work" is super unlikely I don't think I'd toss that theory out entirely. Having lots of childre

> While "having lots of children leads to physically demanding work" is super unlikely I don't think I'd toss that theory out entirely. Having lots of children is usually tightly correlated with having children early, and this absolutely makes gaining post-secondary education far more difficult. Which then correlates pretty nicely with being stuck with physically demanding jobs.