The U.S. Fertility Decline Is Not Due to the Drop in Teen Pregnancies

The Economist recently claimed that half of the U.S. fertility decline is due to falling teen births. That claim was repeated in a recent Manhattan Institute interview with author Rob Henderson. It went viral on social media, with many commenters noting that pronatalists should be celebrating the decline in teen births, not mourning a drop in fertility.

The problem? The stat is completely wrong. In fact, falling teen births only account for about 10-15% of the decline in American fertility.

To begin with, here’s U.S. fertility over time:

The basic trend: fertility rose between 1930 and 1960, declined between 1960 and 1975, increased between 1975 and 2007, and declined again between 2007 and today.

When people talk about “declining fertility” today, they aren’t talking about the drop from 1960 to 1975: most of that decline was just coming off the Baby Boom. U.S. fertility in 2007 was higher than it was in the 1930s.

Rather, “declining fertility” refers to the decline since 2007, the drift to fertility far below replacement rates, and far below what families report desiring.

The figure cited by The Economist, of course, was not about the fertility rate change from 2007 to today. Instead, it referred to birth changes from the early 1990s until today. This is bizarre, because U.S. fertility rose between the early 1990s and 2007! There was no decline!

So, when did teen fertility begin to fall? The chart below shows fertility rates for U.S. women ages 15-19 (note: births to girls under age 15 are not as reliably reported, but were always at least 50% lower than births to older girls, and thus made up a very small amount of total births). Here are U.S. birth rates over time among teens by age:

The key thing to note here is that teen births have been declining for quite a long time. The teen birth rate declined from 1960 to 1975, then rose a bit through 1993, then it declined persistently from about 1993 to today.

That just isn’t the same trend as we observe for the overall fertility rate, or TFR. To put it another way, here’s the share of total fertility deriving from minor moms, i.e. women under 18:

We can see that there was a big boom in the relative importance of teen moms between 1960 and 1975, a plateau from 1975 to 1994, and then a persistent decline from 1994 to today. This kind of analysis can be extended across the entire age range, as in the figure below:

Teen births fell between 1994 and 2007, while later births rose. Teen births declined further between 2007 and 2024—but you can see that the biggest declines are actually for women in their early 20s. The green line for 2024 is below the orange line for 2007 all the way up through age 32, and beyond age 32, it is really only barely higher. The simple fact is that fertility decline has occurred across virtually the entirety of young adulthood. 

Acting as though falling fertility is mainly about declining teen pregnancy is not only absurd but wrong.

Between the ages of 15 and 32, the estimated sum of age-specific fertility rates was 1.66 in 2007 vs. 1.1 in 2024, a decline of 0.56 children per woman ages 15-32, on average. Of that decline, just 0.05 of it can be explained by declines among minors, and just 0.15 can be explained by women ages 15-20. Thus, depending on if “teen” means “non-adult” or “literally has the suffix ‘-teen’ in the number,” between 9% and 26% of the fertility decline since 2007 can be explained by declines in these births.

In other words, between 74% and 91% of the drop in American fertility since 2007 is about declining births to adult women. On the whole, the drop in teen pregnancy is something to be cheered, since teen births often occur outside of marriage, are unintended, and sometimes unsafe. But falling teen births are a sideshow compared to the massive overall decline in U.S. fertility.

Lyman Stone is Senior Fellow and Director of the Pronatalism Initiative at the Institute for Family Studies.