[FiatLuxDave]

Rarely have I seen someone shoot down their own argument with a link quite as effectively as this.

You might want to google those cities, since every single one that I've checked is a small population city surrounded by rural area.

Your argument about cultural influence might be more persuasive if you compared larger cities.

[dlcarrier]

Everyone likes to gatekeep what urban is, to the point that some only consider New York City or even just Long Island to be an urban area. The areas in the linked graph are all recognized as urban areas by the US Census Bureau, and whether you're in Odessa Texas, Provo Utah, Vancouver Washington, or Pasadena California, you're in a similar population density with similar services, except maybe that going to Salt Lake or Savannah airports only takes 45 minutes, instead of the one to two hours it takes to get to LAX from Pasadena.

[PaulHoule]

I don't disbelieve the cultural influence myself but I'm pretty sure that urbanization matters.

I think the master narrative of human civilization is that almost all of us had ancestors working in subsistence agriculture a few generation ago who have moved or are moving into urban areas. This transition is largely complete in the US and Europe, happened explosively in China post-1980 and is about 2/3 complete there and is less far along in Africa and South America. Birth rates go down in this process.