This comes up in every discussion about demographics. But counterintuitively, there are no examples of financial incentives actually fixing this problem.

For example, in 2022 Hungary was spending 6.2% of GDP on such incentives[1], but this only managed to bring total fertility rate up to about 1.6 [2].

It is the same everywhere else. The real reason fertility has declined since the sixties is because people have access to effective birth control. Nobody wants to be a baby factory.

[1] https://abouthungary.hu/news-in-brief/hungary-to-spend-6-2-o...

[2] https://www.macrotrends.net/global-metrics/countries/hun/hun...

Back of an envelope suggests that to really make this work you'd need most women in the 20-40 range to have the job title of "parent" and a lower middle class or more salary paid by the state, so .. 10-20% of GDP? Nobody wants to contemplate just how expensive this is going to be, including the fact that now you have a short-term labour shortage (because they're out of the regular workforce as well!)