Inductivist

When it comes to having kids, it's possible that whites are more sensitive to the cost of living than are blacks or Hispanics. Perhaps the racial differences in fertility are smaller in inexpensive regions. Using General Social Survey (GSS) data, I calculated the mean number of offspring for women ages 40-59 during the years 2010-18.  The GSS records the region of the country in which the respondent lives. There are nine regions: I decided to compare the Pacific (west coast) and West South Central (TX, LA, OK, AR) regions since the former is expensive while the latter is more affordable.


Mean number of offspring
Pacific
Hispanic    2.92
Black         2.08
White         1.75

West South Central 
Hispanic    2.55
Black         2.27
White         2.11

As expected, Hispanic fertility is highest in both regions, while whites are on the bottom. While black and white women have more kids in the WSC region, Hispanic women in the Pacific have bigger families than Hispanics in the WSC, contrary to expectations.

Look at how the racial gap in the WSC is smaller than in the Pacific region. The Hispanic-white gap in the former is .44 kids, while it is 1.17 in the latter. Comparatively speaking, whites benefit from living in low-cost regions.

Do whites benefit when they move from a high-cost to an inexpensive region? The best I could do to answer this question with GSS data was to use a question about where you lived at age 16.  I extended the time span to 2000-2018 to get a large enough sample size and focused on a move from the Pacific to the Mountain region since it was the most common expensive-to-cheap move.

Mean number of offspring--whites

Pacific to Mountain States   2.17
Stayed in Pacific                  1.71

You can see that whites who lived in the Pacific region at age 16 but subsequently moved to the Mountain States averaged more kids than those who did not move out of the region. The move to cheaper regions seems to help fertility.