Summary
With fertility having fallen below replacement level in the U.S., the Congressional Budget Office projects that deaths will outnumber births by 2033. Although some advocates look to higher-fertility immigrants to end the baby bust, the direct impact of immigration on national fertility is too small to achieve replacement level. Furthermore, evidence suggests that immigration indirectly depresses native fertility, especially among the working class.
Direct Impact on U.S. Fertility
The total fertility rate (TFR) of a population is the average number of children that women would have in their lifetimes, assuming their rates of childbearing at each age match today’s rates. Although immigrants do have a higher TFR than natives in the U.S., the presence of immigrants raises the combined TFR by only a small amount. As Figure 1 indicates, the native TFR was 1.73 in 2023, while the overall TFR, which combines both natives and immigrants, was 1.80. The apparent gain due to immigration is just 0.07 children per woman.
Figure 1: Immigration Increases the Nation’s Total Fertility Rate (TFR) Only Slightly

Source: American Community Survey. Data for 2012 is missing because the Census Bureau reports a problem with the fertility variable that year. TFR is the number of children a woman can be expected to have in her lifetime based on current patterns.
Of course, the gain could be greater with more immigration, but the immigrant TFR is simply not large enough to make a dramatic impact. The immigrant share of women of childbearing age already stood at a record high of 15 percent in 2023, and doubling that share would boost the overall TFR to just 1.87.
Reaching the replacement level of 2.1 through immigration would be virtually impossible without reorienting our system toward the few parts of the world that still have high TFRs, such as Sub-Saharan Africa and the Middle East. If imported on a large scale, immigrants from those places may solve the problem of low national TFR — assuming their own fertility does not plummet upon reaching a wealthy country — but their low skill levels and cultural distance from the West would create many new problems as well.
Indirect Impacts on Native Fertility
The analysis above measures the impact of immigration on fertility simply by averaging immigrant TFR with that of natives. In other words, it assumes that a native TFR of 1.73 in 2023 would exist in the absence of any immigration, and that immigration does not alter it. In fact, recent research suggests that immigration impacts native fertility — positively in part, but mostly negatively — through a variety of mechanisms.
Child Care. One mechanism is cheaper child care. A 2015 article in the IZA Journal of Migration finds higher fertility among college-educated, native-born women when they live in places with higher levels of low-skill immigration. The author theorizes that such immigration has made daycare more affordable for these women by lowering the wage of child care workers. Obviously, this native fertility increase is narrowly focused, and one could speculate — although the paper does not — that the childbearing decisions made by lower-skilled natives who may compete with immigrants for jobs could be affected very differently.
Wages and Employment. Indeed, the literature shows that immigrants tend to put downward pressure on the wages and employment opportunities not only of child care workers, but of all the U.S. workers with whom they compete. A book-length report published in 2017 by the National Academies of Sciences, Engineering, and Medicine includes a long list of studies demonstrating that relationship. Workers who experience job instability are in turn less likely to have children, as a 2004 article in the Journal of Population Economics points out.
Housing. Another mechanism by which immigration could affect native fertility is housing costs. A robust literature shows that immigration leads to higher rents and house prices. For example, a 2017 study in the Journal of Housing Economics finds that a 1 percent population increase due to immigration in a metropolitan statistical area (MSA) is associated with a 0.8 percent increase in rents in that MSA, along with a 1.6 percent increase in surrounding MSAs. For house prices, the increase was again 0.8 percent in the target MSA, but 9.6 percent in surrounding MSAs. The large spillover effects are likely due to native flight from high-immigration areas.
If couples are unable to afford sufficient housing, they may not have as many children as they desire. That is the finding of a 2014 paper appearing in the Journal of Public Economics, which estimated a 2.4 percent decrease in fertility among non-homeowners for every $10,000 increase in home prices. There is a twist, however, in that fertility actually appeared to increase among people who already own their homes, leading to a combined positive effect on fertility of 0.8 percent immediately following a price increase. A more recent study in Labour Economics employs a cross-country analysis in which the combined effect is negative. In either case, the immediate impact of immigration on native fertility is not large, but the positive impact that high earners may enjoy comes at the expense of lower earners.
In assessing the linkage between housing prices and fertility, it is important to distinguish between the immediate impact on fertility and the lifetime impact. When housing prices change, do women merely shift their planned childbearing to a different time, or is their lifetime fertility affected? Although the shift theory is plausible for the established homeowners who have more children when their equity increases, a lifetime impact is more likely for young women still searching for suitable housing. A study published last year in Population Research and Policy Review shows that renters in expensive housing markets tend to delay childbearing, which in turn decreases their expected lifetime fertility. “Even temporary housing unaffordability … might have long-lasting effects on the age pyramid,” the authors write. A 2009 article in Regional Science and Urban Economics similarly finds that completed fertility is lower in metropolitan areas with high housing costs.
Diversity. Immigration could also affect native fertility by increasing the nation’s ethnic diversity. A new working paper out of Boston College documents a negative association between diversity in a locality and the number of children that residents have.1 The relationship holds across many places and time periods, under a variety of model specifications. It may be due to “homophily”, the statistical tendency for similar people to associate with each other, in that diversity can make finding a same-ethnicity marriage partner more difficult. It may also be due to the broader decline in community engagement that political scientist Robert Putnam observed in diverse areas. In any case, a back-of-the-envelope calculation suggests that the increase in diversity caused by immigration could have lowered native TFR enough to fully negate the impact of immigrants’ higher fertility on the national TFR.2
Combined Effects. The studies cited above show how immigration impacts a particular variable (such as housing costs or diversity) and then shows how that variable impacts fertility. What is the combined effect of these variables on fertility? To answer that, we need to examine the immigration-fertility linkage directly. In a 2021 report, my colleagues Steven Camarota and Karen Zeigler found a negative correlation between the immigrant share of an MSA and the birth rate of native-born women. The relationship was strongest among working-class women living in the 50 largest MSAs, and it persisted when controlling for variables such as the average income and education in each MSA. The analysis is only suggestive, however, because the data set is cross-sectional with a limited set of control variables.
Observing what happens to fertility before and after a sudden immigrant influx could better establish causation. One such influx occurred in Miami in 1980. After Fidel Castro announced that anyone wishing to leave Cuba could do so via the port of Mariel, 125,000 Cuban immigrants came to Miami between April and September of that year. This “Mariel Boatlift” is a kind of natural experiment — albeit limited to one city — that economists have used to investigate the impact of immigration. A 2018 article in the IZA Journal of Development and Migration compares the change in fertility in Miami after the boatlift with trends in fertility in a control city that did not experience an influx.3 The results indicate that, relative to the control city, fertility declined 3.4 percent in Miami between 1980 and 1984. The effect was due to lower fertility among renters rather than homeowners.
Relative to the control, Miami fertility appeared to largely recover by 1988. However, we should not assume that immigration-induced fertility declines are temporary. For one thing, domestic migration as a response to the immigrant influx could disguise the impact. If certain Americans move away from Miami (or decline to move to it) because immigration has made it difficult for them to build a family there, while those who remain experience no fertility drop, then the fertility rate in the city would appear to “recover” — but only because of compositional changes in the population. Furthermore, immigration is a continuous process. Even if the U.S. could absorb a one-time wave of immigration without a long-term change in fertility, the long-term never arrives when every year brings another wave.
Conclusion
U.S. fertility has fallen below replacement level, but immigration will not generate many more babies per woman. Although immigrants have a higher TFR than natives, it is not nearly large enough to bring the overall national rate back up to replacement. In fact, immigrants appear to depress native fertility, reducing or even eliminating the small gain in TFR that they bring to the national average.
While some effects of immigration can indirectly boost native fertility, such as cheaper child care and greater home equity, the weight of the evidence points to immigration causing a net reduction in fertility among natives. These reductions are due in part to destabilized employment, higher rents and home prices for first-time buyers, and increased ethnic diversity that reduces community engagement. In each case, working-class Americans bear the brunt of the impact. They face greater competition from immigrant labor than do higher-income Americans; they are more likely to rent than own a home; and they have less means to move away from areas that they no longer find culturally conducive. It is often said that immigration is not a “left-right” issue so much as it is “top-down”,’ meaning the negative impacts tend to fall on the working class. The impact of immigration on fertility appears to be no exception.
End Notes
1 The paper uses the term “diverse” in the literal sense of different groups living together. It is not a synonym for non-white. A city such as El Paso, which is nearly all Hispanic, would be considered non-diverse in this paper’s analysis.
2 This calculation uses the Herfindahl index of ethnic homogeneity, which is the sum of the squares of the population shares of each ethnic group. A higher number means more homogeneity. Based on the Pew Research Center’s 2015 estimation of American demographics in the absence of post-1965 immigration, immigration accounts for just over half the decline in the Herfindahl index between 1965 and 2015. Under the Boston College author’s preferred specification, increased diversity accounts for a reduction in the TFR by about 0.12 or 0.13 since 1971. Therefore, we can estimate that immigration reduced TFR by approximately 0.06 to 0.07. As discussed in the “Direct Impact on U.S. Fertility” section above, this reduction has about the same magnitude as the increase in national fertility due to immigrants’ higher TFRs.
3 The control city is actually “synthetic” — it is a combination of real cities weighted to best match the socioeconomic characteristics of Miami prior to the boatlift.
* Republished from the original publication by the Center for Immigration Studies.