Anarchism

Religion has essentially no bearingon births per woman. Religious societies like Ukraine have some of the lowest birth rates, while secular countries like Finland have higher rates.

It's almost a perfect inverse linear correlation between GDP/capita and births per woman. The only outlier is Israel, which is a highly polarized society with high levels of child poverty.

When child mortality goes down, births go down too. That means that basic nutrition‌, vaccines, and basic neonatal health care are responsible for the bulk of nativity reduction. The rest can be attributed to access to contraceptives, compulsary education and women in the workforce.