U.S. fertility falls; women delay pregnancy

America’s fertility is in precipitous decline. Our team of forecasters at Demographic Intelligence projects 3.84 million births in 2017, down from about 3.95 million in 2016.

The latest data from the Centers for Disease Control and Prevention, reflecting births as of the year ending in September 2017, shows the total fertility rate at 1.77 lifetime births per woman, down 3.8 percent since 2015, and down 16.4 percent since its recent peak at 2.12 percent in 2007. (Replacement rate in developed countries is 2.1 percent.)

The total fertility rate is a measure of how many children a woman entering her reproductive years today could expect to have, if age-specific fertility rates remain constant over time.

But what began as sharp declines in pregnancy and childbearing among teenagers — typically considered a socially desirable result — has slowly spread up the age cohorts, first to women in their early 20s, then to those in their late 20s. And now fertility decline has set in for women even in their 30s.

Data from the General Social Survey shows that the share of people 18 to 30 who have not had sex in the past year has risen to nearly 20 percent, while the share having sex at least two times a month has fallen to about 65 percent.

Diminished face-to-face interaction, and increased use of pornography, may explain the fall in sex, and both of those trends may be explained by the rise in cellphone usage and other screen time.