U.S. fertility has been declining for the 15 years since the Great Recession and it is now below replacement rate. While many are aware of this fact, fewer are aware of the demographic factors driving the topline numbers.

A variety of demographic groups are responsible for the post-2007 decline in U.S. fertility, and understanding which demographic groups are major contributors may provide hints about the underlying causes.

First, fertility has declined across younger demographic groups. This is partly due to a significant decline in births for teenagers (Figure 1), which peaked in the 1990s and fell 75 percent from 1991 until 2020. Teen fertility decline accelerated since 2007, just as U.S. fertility began its most recent drop.

The decline is also due to a decline in births for women in their twenties, particularly women in their early twenties, for which births have declined by nearly fifty percent since the early 1990s. Similar to teens, births declined more steeply for women in their twenties beginning during the Great Recession. As fertility for U.S. teenagers and twenty-somethings has declined, fertility for women in their thirties and forties increased, but not enough to offset the decline for younger women.

Fertility also declined across racial and ethnic groups: Hispanic, Black, and White women’s fertility fell, but Hispanic women’s fertility declined most dramatically, by over one-third since 2007 (Figure 2). In other research, Kearney, Levine, and Pardue find that Hispanic teens are the specific demographic group responsible for the largest share of the overall U.S. fertility decline.

Although U.S. Hispanic women have traditionally had higher fertility than other groups, it is not altogether surprising that Hispanic women are also experiencing fertility decline. Kearney and Levine find that the decline in fertility for Hispanic women is driven by both native and foreign-born Mexican-American women, and fertility in Mexico has fallen dramatically since the early-70s. Today, the total fertility rate in Mexico is below replacement rate, at 1.80 children per woman. Although this is above the U.S.’s fertility rate, Mexico’s fertility rate is converging with the U.S. and industrialized countries’ fertility rates.

Immigration patterns may also help to explain the recent decline in births for Hispanic women. Net migration from Mexico to the U.S. was negative during 2005–2014, and the number of foreign-born Mexican women relative native-born Mexican women fell during this period. This matters for fertility purposes because foreign-born women tend to have a higher fertility rate than native-born women.

Finally, fertility varies with education. Women without a high school degree saw the largest declines in fertility, followed by women with a graduate degree (Figure 3). The population of women without a high school degree overlaps with teenage women, and this tracks with the decline in teenage fertility.

It is interesting that fertility decline has affected those with the greatest and least education most. For women with graduate degrees, presumably opportunity costs for childbearing are higher than for any other group, and women with graduate degrees also tend to be older than other groups, yet birth rates for these women are highest. Meanwhile, the group of women without a high school degree includes teenagers that have successfully reduced unintended births perhaps as a consequence of increased access to contraception or due to the effect of targeted media programming.

What to conclude from this? Fertility is a complex issue with a variety of plausible explanations. But given the demographic groups most affected by decline, some policies seem more or less likely to increase fertility for policymakers intent on doing so.

For instance, recent evidence suggests that increasing workplace flexibility would provide more educated women with additional options for combining work and family life. Moreover, although fertility is falling for Hispanic women, it remains higher than for other groups, and liberalizing immigration laws could increase U.S. fertility in the short-term and, if sustained, offset population decline in the longer term. On the other hand, significant fertility declines among groups like teenagers don’t present great options for policymakers intent on boosting fertility rates.