I have to call BS on this. even the article itself contain 'While it is impossible to definitively trace a causal link between land use restriction and fertilit

I have to call BS on this. even the article itself contain 'While it is impossible to definitively trace a causal link between land use restriction and fertility, the results here suggest that the two are strongly related in the data.' A correlation is shown, but no causation. If I needed to speculate, even without resorting to hidden variable impacts, I'd say the market for 'exclusive' housing in less child friendly environments would tend to be dominated by singles and couples with large disposable incomes, potentially resulting from being more career than family focused. 'We can't financially afford having another baby, so we wont' does not seem to hold at all as a rule for primary driver in both present and historic worldwide reproduction data. If anything, it's the reverse.