Summary: We relate the decline in the birth rate to two demographic factors closely related to women’s fertility patterns: marriage and educational attainment. Married women are at least three percentage points more likely to have a child than unmarried women, and at the same time, marriage rates among women 25 to 29 have fallen 15.9 percent since 2006. Women who complete 4 years of college are less likely to have a having a child, while completion rates of 4 years of college have risen by 10 percent in the past decade for women.
Over the past decade, fertility has declined rapidly in the United States – from a Total Fertility Rate (TFR) of 2.2 births per woman in 2008 to just 1.7 in 2019. Initial reports suggest that the effects of the Covid-19 pandemic has accelerated this trend. Although some of the pandemic-related fertility decline may be due to families waiting to have children, rather than changing their desired family size. If so, fertility should rise near the end of the pandemic and in the years immediately following the pandemic. This post highlights two demographic trends in women related to the past decade’s decline in fertility: marriage and education.
Marriage and Fertility
Timing of marriage, and especially whether a woman marries younger or older, has historically been a strong predictor of women’s fertility patterns. Figure 1 depicts age-specific marriage rates among rearing-age women in 5-year age cohorts from 2006 to 2019, calculated from the American Community Survey (ACS). Over the period observed, marriage rates among women aged 25-29 fell by 15.9 percentage points.
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Figure 2 shows the percentage of rearing-age women who had a child in the previous year, separately by marriage status.1 Over the entire period observed, married women are at least three percentage points more likely to have given birth in the past year than unmarried women. Furthermore, over the past decade, unmarried women of childbearing age have become increasingly unlikely to give birth: the probability drops a full percentage point over the observed time frame.
Education and fertility
In women, educational attainment (especially university attendance) is also closely related to decline in fertility.
Figure 3 shows college education rates among women age 25 and older. The figure shows a linear increase in the completion of four years of college: in 2006, only 30.5 percent of women between the ages of 25 and 49 completed four years of college, compared to 40.7 percent in 2019.
Figure 4 plots the percentage of rearing-age women who had a child last year, separately by whether she completed 4 years of college. The birth rates for each of these groups of women declined a full percentage point over the observed period. In 2019, women aged 15-49 with at least four years of university were 0.8 percentage points less likely to have had a child in the past year.
By examining age-specific fertility rates, marriage rates, and trends in women’s educational attainment, it is clear that many women are delaying fertility and ultimately having fewer children. These factors are not isolated, but also interact with each other. A young woman who graduates college is more likely to marry and have children after age 21 and enter the formal labor market. Because she is a worker with a college degree, she is likely to earn a higher income than women without college degrees, which means that her opportunity cost of leaving the labor market to have children will be higher than it would otherwise have been if she earned a lower income. Additionally, if women worry that they will advance in their careers at a slower rate if they go on maternity leave, they will also be discouraged from having children. Furthermore, high childcare costs provide a disincentive to parenthood.
The decline in birth rates in the US has also been observed in most developed countries around the world. With the fertility rate below the 2.1 births-per-woman replacement rate, the resulting population age distribution has many policy implications. One concern about fertility decline is that per capita federal debt will increase for future generations ceteris paribus. For example, programs like Social Security that are pay-as-you-go systems will not have enough working-age people paying into the program to support the population of retirees without fundamentally changing payroll tax rates or Social Security benefit payouts . Relatedly, there are concerns that a shrinking population will result in a smaller workforce and slower economic growth. Still others argue that a declining birth rate can have potential positive effects, such as reducing infrastructure costs, and alleviating ecological burdens and natural resource constraints. One must also keep in mind that increasing immigration may also offset some of the population decline (and effects) that current trends in the birth rate would cause.
This analysis was conducted by Maddison Erbabian, Austin Herrick and Victoria Osorio. Prepared for the website by Mariko Paulson.