Let’s just focus on how cars and car culture are reducing birth rates. Nobody wants to chuck their kids into the back seat without a carseat any more. Laws aren’t the problem.
These seem like particularly specific excuses. If you are not into having kids, there are many different ways to rationalize that (but why?). If you are into kids, you'd have to overcome all sorts of pain and suffering, car culture is by far not the worst of them.
(Father of 4, 39 y.o., non-religious.)
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Cars and car culture probably increased birth rates in the last few decades to begin with!