Smartphones seem to be directly linked to a worldwide crash in the birth rate.
It is "quite plausible that the modern digital media environment has had profound effects on society that have led to a decline in romantic coupling", said Melissa Kearney, professor of economics at the University of Notre Dame. She has to talk that way, being an academic, but what she means is that people are doomscrolling, not copulating.
That's old news, but the evidence for it is more impressive because it is data-based. That's what we have social scientists for, and John Burn-Murdoch, a columnist with the Financial Times, realised that you could quantify the data if you talk to enough of them. So he did, and learned that the big drop in the birth rate happened precisely when people got smartphones.
