by Scott Yenor (@scottyenor) and Lyman Stone (@lymanstoneky)
America’s partisan divide is manifest in attitudes toward family life and in actual family practice. Democrats increasingly seem to be the party of single women and the childless. Republicans, by contrast, are increasingly the party of those who value marriage and children. This partisan divide on family is growing around the world.
In the United States, counties that supported Donald Trump for president in 2024 had significantly higher birth rates than counties that supported Kamala Harris, as a previous IFS study showed. The higher Trump’s margin of victory, the higher the birth rate. The 20% of counties where Trump had the highest margin had a total birth rate (TFR) of 1.76 (above the national average of 1.63 in 2024). The higher Harris’s margin of victory, the lower the birth rate. The top 20% of counties that voted for Harris had a TFR of 1.37.
State-level data reveals a similar relationship between partisanship and fertility. Democratic states have much lower fertility rates than Republican states. But why do conservatives have more babies?
