In the United States, white Catholics no longer have higher fertility than white
Protestants, but women with conservative beliefs on abortion (whether Catholic,
Protestant or Jewish) bear nearly two-thirds of a child more than those with pro-choice
views. (Kaufmann, Goujon et al. forthcoming) Conservative denominations also have
higher fertility than more liberal ones, not to mention seculars. (Skirbekk, Goujon et al.
forthcoming) American research also suggests a significant link between various
measures of religiosity (congregational participation, denominationational conservatism,
attendance) and fertility. Participation in congregational groups is especially important.
(Hackett 2008) During much of the twentieth century, women in conservative Protestant
denominations bore almost a child more than their counterparts in more liberal Protestant
denominations. This was the main reason why conservative Protestants increased their
share of the white Protestant population from roughly a third among those born in 1900
to nearly two-thirds of those born in 1975. (Hout, Greeley et al. 2001) Individual-level
relationships are reproduced through compositional effects at the state level, hence higher
white fertility in states with large Mormon or evangelical Protestant populations. Indeed,
there was a correlation of .78 between a state’s white fertility rate and its 2004 vote for
George W. Bush, an effect strongly mediated by religious traditionalism. (Hout, Greeley
and Wilde 2001; (Lesthaeghe and Neidert 2006). After all, 78 percent of white
evangelicals voted for Bush in 2004 (including a majority of Hispanic Protestants), as did
solid majorities of theologically traditionalist Catholics and mainline Protestants.
Seculars and theologically modernist Christians of all denominations, by contrast,
overwhelmingly backed John Kerry. The 2008 election shows only a modest change in
this pattern. (Guth, Kellstedt et al. 2005) (Guth 2008)