Educated women tend to have fewer children.

(Also fewer child deaths)

Educated men also father fewer children. Takes two. Educated people with the means will choose when to reproduce.

Anecdotal observation / hypothesis:

- there's an inverse relationship between quality of life and density, even within individual households

- there's a higher premium on space in urbanized areas than in rural areas

- there's been a move towards urbanization across the world, high HDI, low HDI, high religion, low religion

I propose something similar to Parkinson's Law: Average family size expands (or contracts) to fill the physical space that is economically viable for a given individual/family.

Rationally, this couldn't be the only factor, given density and urbanization patterns predate the more rapid fertility decline in recent decades, but as one more factor on top of a pile of others that may also be contributing to the trend, I think it could plausibly play a contributing role in the decline.

Thoughts?

I think it matters in how you define quality of life, for one.

Take a family of five kids and give them a bedroom for each kid when young and they’ll end up clustering in one or two.

I think space and other pressures may have their place as causes, but are mostly downstream from whatever the root issues are.

>Take a family of five kids and give them a bedroom for each kid when young and they’ll end up clustering in one or two.

Do you have anecdata on this? I grew up with a single sibling, and we had to share a room as young children due to economic circumstances, but we were both very excited to get our own rooms when our parents bought a larger house.

I have no kids of my own and don't plan on having any, but I'm fascinated by this perspective.

My experiences is that below the age of six, they ALL want to cluster together. Above six it starts to sex-segregate naturally, and around teen years the desire for their own space soars.

But even then they often want congregation, but the ability to retreat. I sometimes think the perfect “large family” house would be tons of tiny bedrooms but lots of common areas. Almost college dorm-like.

Another anectdata - I’ve never met a family with same-sex twins where the twins did NOT live in the same room, even when there was ample space to not do so. I presume the triplet case is even stronger.

I have 8 kids, they cluster at night, sing to each other, recite poetry, and talk late into the night.

It’s more similar to how families slept for millennia.

sounds like a potentially abusive situation.

Iran specifically was super worried about overpopulation in the 80s and the government began a massive program to decrease childbirth rates. With things like government messaging on small families and providing free birth control. Here is a graph that shows it https://www.macrotrends.net/global-metrics/countries/irn/ira...