So it’s a while ago now but I did my masters dissertation on exactly this - in relation to Italy but some of the same factors are at play here. I’d argue causes are both economic and social. https://twitter.com/edconwaysky/status/1350028146544947200

First a personal bit. Couple of years ago, I said to my mother (I’m the youngest of 3): “none of us will have 3 kids.” She looked bemused: “3? It’d be great if one of you just had 1.” I have finally provided the first grandchild. Aged 36.

Obvious issue is space - an economic problem. My parents bought a big house for relatively little. We are in a 2 bed with little hope of buying a bigger house (unless we leave London) and neighbours who will object to us extending. And we’re lucky/ pretty privileged.

Then there’s workplace insecurity. I know a huge number of women who have suffered maternity discrimination. It may be illegal but that does not stop it. This might mean you postpone children or “minimally reproduce” as one demography prof put it( ie have 1)

The more women postpone having their 1st child, the lower the average total fertility rate will be. BUT the stats sometimes fail to pick up that women are delaying having kids, rather than not having them at all.
Over 40s is where fertility rates are rising.

People talk about other factors (eg worries about climate change, brexit gloom etc). These sorts of factors can play a part - the example always used is the collapse of fertility in east Germany after the wall came down- but they have to be pretty extreme to have an effect

In Italy, one of the main causes that led to fertility rates dropping was inequality - women had good prospects in the workplace but were still expected to do so much at home. The pandemic has highlighted that burden of childcare still usually falls mostly on women.

And the cost of childcare in the UK is exorbitant anyway. That combined with the high cost of housing inevitably limits fertility.
Lots of us have been saying this for years - govs ignore demography because they look short-term, but they shouldn’t. Has huge impact

I should add that I’ve talked about the “burden” of childcare - obviously it can be a joy too (see pic). My demography prof used to say the remarkable thing was that people continued to have children at all given the cost: 18 years of partial house arrest + £150,000...