While I believe this article to be correct, Germany is an interesting counter-example:

Germany first introduced mandatory child car seat laws on April 1, 1993. [1]

That year, fertility was at 1.28 kids per woman. Since then, it has increased to 1.62.

[1] https://de.wikipedia.org/wiki/Kindersitz

https://www.macrotrends.net/global-metrics/countries/deu/ger...

You can’t compare those numbers because the population in 1993 and today comprises different groups who are materially different in terms of fertility rate. Last year, the fertility rate for women with German citizenship was 1.23.

The other major change is that in 1990, you had a reunification of east and west germany. Fertility rates in East Germany were low before reunification and collapsed right after reunification. But they recovered from the early 1990s to the late 2000s. So the 1993 aggregate average is artificially low. In neighboring France, the fertility rate in 1993 was 1.7.

Could be as if you live in a city in Germany you don't necessarily need a car?

But I would be surprised if car seats are the main driver here in any case.

Those who have children can’t afford a car.