birth rates are determined by thing: women's rights. if women can vote, own property, work outside the home, go to school, or if they do anything during their prime fertility years of 16-25 besides get married and have babies, then birth rates go down below replacement level. the bottleneck of human populations has always been and will always be women's wombs which only work well for about a decade maybe two if you stretch them, and a baby takes basically a year. if you want women to have babies during that time, then they need to be focused on that, rather than getting a bullshit degree so they can ruin the economy with an even more bullshit job.
United States