U.S. birth rates slide as Millennials enter the age of marriage and childbearing

[Mr. Morden]

I'm over 30, so of course I have friends who have children (both here in Oz, and among my friends in the US).  However, the max. number of children that any of my friends have is two.  Some have zero, some have one, and some have two, but that's as high as it goes.  So no, you can't count on Mr. Morden's social circle to keep up with replacement levels.

[Mr. Morden]

Above National Average
Below National Average

Top Half Above National Average
Bottom Half Above National Average
Top Half Below National Average
Bottom Half Below National Average

Interesting east-west divide.  Isn't there also an east-west divide in the male-to-female ratio, with the eastern US tilting female, and the western US tilting male?  Is there some relationship between that and the birth rate?  Which also begs the question: Is the birth rate defined as the number of babies born per year per person, or per woman, or per woman within a certain age range, or what?

[Mr. Morden]

Incidentally, from a quick Google search, here's a table of the male-to-female ratio by state, which also lists the age breakdown by state:

http://names.mongabay.com/data/2010-male-to-female-sex-ratio-state.html

I'm too lazy to make my own map out of that, but I'm sure there are some correlations with the birth rate map.