This has happened to every single society [*] as it industrializes [0], and offering extensive support and incentives to parents (e.g. as has been tried in Scandinavian countries) does very little to reverse this trend [1, 2]. My hypothesis is that as societies industrialize, they afford their population more and more activities that are simply more fun and rewarding than having children. So many people I know put of…
One could make the point this is less about industrialization causing a change in behavior, and more chemical pollution destroying fertility. Of which we have plenty of concrete evidence.
And most fertility issues people do encounter can primarily be explained by attempting to have children decades later than is biologically optimal.