I have a different pet explanation from the other replies here, and I honestly don't get why it's not talked about more.

Basically, our economic reality and expectations have come into conflict with biology and human lifespan.

If you want a secured dignified life and basic prerequisites to starting a family, every year that takes a little longer. And these days, almost everyone wants that dignified middle class life before they start a family.

A degree, an advanced degree, a good enough job, sufficient housing, a little fun to boot. Not until 25, 28, 30, 33, 35.

But we're supposed to have children in our early 20s. That's when we're strong and energetic enough, with good backs, and grand parents fit and willing to pitch in.

When we finally feel ready in our mid 30s, we find that time has conspired against us. Our parents are far away and often ailing and demanding care and attention. We have less energy and more stress and dread the lost sleep. We have the wisdom and worldliness to know just how hard this is going to be. And once we've metabolised all those things, that's when we realize that conception is no longer a question of a great night out and a few drinks. How many kids will be born at the end of that gauntlet? We're finding out right now.

This is a real thought process people are contending with. There's also just the simple fact that kids are liabilities more so than assets. That's not been the case through most of human civilization.

I wouldn't limit it to economics either. Socially children are restricting. If you want to be free to travel, move, leave the house on a whim, etc. then kids will interrupt your plans/logistics.

There is the idea floating around in Europe, to nullify people’s student debts if they have children.

So two kids during university would mean even the measly amount you have to pay back for an European subsided degree would be gone.

I do hope that will be put into effect.

I also believe that this will be better for gender equality than all the other measures taken so far.

I was in too many meetings, where the CV of a young woman was critically evaluated for her propensity to get pregnant as soon as the probationary period was over.

Also, women's overall fertility drops off a cliff after 30, but this is downplayed because the extreme sensitivity of the issue.

Yes, absolutely. I agreed with the parent too, but I think your explanation is not as different as it seems. I think your framing is just more direct and correct.

However, one big caveat:

"If you want a secured dignified life and basic prerequisites to starting a family"

What you're saying is more relevant to the state of already-developed nations, that are now all in a slow decline. Not so much to newly developed nations, slowly on the rise.

That context established:

The common "we can't afford children" explanation is certainly a significant part of the equation, but I have never bought that it is the biggest reason. Children are expensive, but highly subsidized, and just not expensive enough to explain the whole picture. Your explanation is, I think, the One Big Thing. So many adults today grew up seeing middle-class life as very attainable with a college education and a work ethic. Then, as they became adults, that "attainable" reality inched away as fast as they progressed toward that goal.

The big, tough thing to discuss (tough because of the modern obsession with attacking "entitlement"), is that humans react much more strongly to change in state than to the state itself. E.g. if Alice grows up in a local culture where most people are poor, and Bob grows up in a local culture where most people have little houses and little yards and low crime, and then Alice and Bob both end up poor, then Bob is a lot angrier than Alice. Bob shakes his fist at the world more, and is more likely than Alice to choose to delay having children until he attains what he thought was a totally reasonable American aspiration.

This is highly parallel to the parent's notion of "not having children in order to pursue other things". It's not just that people don't want children - it's that they want children and middle-class lives, and feel uneasy choosing children when it feels like one more bump on the path to a middle-class life.

We're also teaching the younger generation imminent climate apocalypse is coming, and therefore bringing kids into this dying world would be cruel, or at best contributing to the problem.

(And now there's also an AI apocalypse of some kind on the way even if the climate situation can be resolved/survived. And the ever-present threat of WW3 seems closer now than ever)

I agree. It comes down to the opportunity cost for women to have babies.

On pre-industrialized societies, women have barely a choice. On industrialized ones they do. And it turns out that, when given the choice, they choose not to have babies.

So support should be provided for incentivizing younger parenthood then, like guaranteed tuition assistance per children born?