There are some who know the answer as far as "fixing" the fertility rate goes, but a modern society which isn't used to it will not like the methods needed to accomplish such a goal.
Does it involve -- at the cost of a modest productivity decline overall due to the requisite reduction of workforce -- incentivizing monogamous heterosexual marriage, having kids in wedlock, homeownership, in-home childcare (i.e. stay-at-home mothers), substantial parental involvement in education, and conversely
disincentivizing "pride," gay (non-reproductive) marriages, renting, single living, "both parents work" households, and so on?
And by "incentivize" I mean stuff like tax credits per-child (only for married biological parents -- no more infinite welfare hacks for single mothers), reduced-or-no-cost pre- and post-natal medical care for married couples, reduced tax burden for single-income married couples with kids (higher standard deduction and lower tax rate overall), scholarships and trade school vouchers for children of married biological parents, and so on?
Disincentivizing would amount to relieving single mothers of their infinite welfare cheat (grandfather current whores so the bellyaching isn't deafening), making gay couples and singletons pay higher taxes because they're not contributing to society's population growth in its preferred way (i.e. in monogamous heterosexual marriages), and taxing "power couples" more for focusing on careers instead of family building.
Is that a decent guess? Because I think it'd be funny (and would probably work). If you're living a lifestyle that produces children in a stable home, you get perks. If you're living a life of debauchery, depravity, or even just flying solo, you don't. If you can sustain it on your own, more power to you, but you're gonna help make it easier for others to breed under ideal circumstances.
