Fertility Rates Of Conservatives Vs. Liberals In The United States

As can be seen, the Republican fertility advantage is relatively stable across elections. It even shows up in a panel model, suggesting that as counties become more Republican, their fertility rates tend to rise relative to the national average. The use of state controls (and some robustness tests I ran in large states with many counties) suggests this effect isn’t driven by unique features of states: within Red states or Blue states, and controlling for county racial and ethnic characteristics and population densities, Republican counties have higher birth rates.

This is particularly astonishing given that Democrats perform very well in counties with many Hispanic and black voters, who have higher birth rates than non-Hispanic white Americans (and indeed, the more non-Hispanic whites in a county, the lower its birth rate in my models). The relationship is also unchanged if the sample is restricted to only very-high-density counties, such as those representing the center of major cities. In other words, the Republican “fertility advantage” does not arise from more rural counties with higher birth rates, and it exists despite the fact that much of the Democratic Party’s electoral base is among racial and ethnic groups with higher birth rates in general. The split I identify isn’t about race or urbanization or region of the country: it’s about family. Within racial- or ethnic-groups, within states or urbanized areas, the more conservative areas tend to have more babies.

In the 1970s, there was little or no difference in fertility rates between liberal and conservative women. But by the 2000s, completed fertility for liberal women had declined markedly below that of conservative women. In recent years, the gap in childbearing between young conservative and liberal women has really opened, which may portend a bigger gap in the coming years...

Before the 1990s, fertility differences by ideology were small. Women over age 45 had no difference in completed fertility, and women of all ages (but with controls for year of age) had only a small difference. There was, however, already a difference in ideology: conservative women reported a childbearing ideal about 0.12 kids higher than liberal women, which is a small, but significant, difference.

For the period after 1995, however, gaps grow. Conservative women over age 45 had about 0.25 more children on average than their liberal peers, an effect which in fact shows up throughout the age distribution once the “over 45” restriction is relaxed. The gap in fertility ideals grew larger as well.

In other words, the “family gap” between conservatives and liberals is a new phenomenon. It’s only in the last two decades that conservatives began to reap a fertility advantage. But it’s not just a fertility difference: if controls for marital status are removed, the conservative fertility advantage gets even bigger. That is, conservatives are simply more likely to be married than liberals. Thus, there is a conservative-liberal gap on marriage and separately on odds of childbearing conditional upon marital status.^[1]