"Call this the Joe Biden-baby-boom hypothesis, which we may be about to test: If you spend on family benefits and run the economy hot enough, maybe fertility rates will finally begin to float back up. This is the ideal scenario for pronatalist liberals, because it would mean more kids without more social conservatism. The second scenario for a fertility recovery, though, involves exactly that: a kind of neo-traditionalist turn, answering the socially liberal swing of the last two decades, that leads to people marrying earlier and having more kids for reasons of values rather than just economics.... [A] third possibility is that a deep fertility decline is more likely to end gradually, through a kind of slow selection process rather than abrupt conversion. By selection I mean that as fewer people have children, the ones who do have kids will be an increasingly distinctive population — not specifically conservative or religious, necessarily, but couples who will have written new scripts for romance, discovered new models for child rearing and burden-sharing, in a cultural and technological landscape that’s torn the older models up. So then the children and grandchildren of these trailblazers, inheriting both the new models for family formation and the world itself, would be the ones who drive some future baby boom."
From "How Does a Baby Bust End?/Three scenarios for a more fertile American future." by Ross Douthat (NYT).
From the comments at the NYT: "It should tell Mr. Douthat something that most of the top comments are from women. Guess what. Women, given any kind of agency at all--which includes education and the ability to support oneself--don't want to have hordes of kids. And if there is anything the planet doesn't need, it's more humans than existing sociopolitical forces are already grinding out. The real problem is to empower those women in oppressive, patriarchal, monotheistic cultures to have the economic, psychological, and political power to say NO more kids than they themselves want. Not to figure out how to con Caucasians (because that's Douthat's subtext) into having more."