Birth Rates Among Immigrants in America
Comparing Fertility in the U.S. and Home Countries
Analysis of data collected by Census Bureau in 2002 shows that women from the
top-10 immigrant- sending countries living in the United States collectively
tend to have higher fertility than women in their home countries. As a group,
immigrants from these countries have 23 percent more children than women in
their home countries, adding to world population growth.
Among the findings:
• In 2002, immigrant women (legal and illegal) from the top-10
immigrant-sending countries had 2.9 children on average, compared to a fertility
rate of 2.3 children in their home countries — a 23-percent difference.
• Among Mexican immigrants in the United States, for example, fertility
averages 3.5 children per woman compared to 2.4 children per women in Mexico.
Among Chinese immigrants, fertility is 2.3 in the United States compared to 1.7
in China. Immigrants from Canada have 1.9 children compared to 1.5 children in
• While immigrants from the top-10-sending countries have more children than
women in their home counties, for immigrants from three countries — India,
Vietnam, and the Philippines — immigrant fertility is lower in the United States
than in their home countries.
• Immigrants in the United States can differ in important ways from the
general population of the countries they come from. If we adjust for their
education level, which is a good predictor of fertility, we find that the gap
with their home countries actually grows — from being 23 percent higher to 33
• Put a different way, given the education level of immigrants and the
fertility of similarly educated women in their home countries, one would
expected immigrants from the top sending countries to have 2.15 children on
average in the United States, not the 2.9 they actually do have.
• As for legal status, we estimate that the birth rate of illegal alien
women was 3.1 children on average in 2002, or about 50 percent higher than the
two children natives have on average. The birth rate for legal immigrants is
2.6, or about one-third higher than that of natives.
• The high fertility rate of illegal aliens seems to be due primarily to
factors other than their legal status, such as culture and educational
• We have previously estimated from birth records that there were 380,000
births to illegal aliens in 2002, accounting for nearly 10 percent of all births
in the United States.
• If illegals are allowed to remain in the country, either as illegal aliens
or legal residents, births alone will add some four million people to the U.S.
population over the next decade.
• While immigrant fertility is significantly higher than that of natives,
their presence in the United States is not the reason the overall fertility rate
in the United States is much higher than in other western countries. Fertility
in the U.S. is roughly 2.0 children, with or without immigrants.
• New immigrants (legal and illegal) plus births to immigrants add some 2.3
million people to the United States each year, accounting for most of the
nation’s population increase.
• Immigrant fertility differs by education level much more than that of
natives. For example, immigrants without a high school degree have 3.3 children
on average, 74 percent higher than the 1.9 children for college graduate
immigrants. In contrast, native high school dropouts have 2.3 children on
average, only 27 percent higher than the 1.8 fertility for native college
• Because immigrant fertility differs so much by education, immigrants now
account for more than one in three births to mothers without a high school
nation’s immigrant (foreign-born) population has grown in recent years, a good
deal of research has been devoted to their socio-demographic characteristics.
However, less attention has been paid to their fertility. Children born to
immigrants are probably the most important long-term effect of immigration. This
study explores immigrant birth rates with particular focus on how they differ
from women in their home countries. Studying immigrant fertility is necessary in
order to understand immigration’s impact on U.S. and world population growth as
well as its effect on public services provided to children. In addition,
fertility can be seen as a measure of immigrant integration. If people are
choosing to have more children, this may indicate that they feel relatively
optimistic about the future. Only recently has data become available to study
immigrant fertility in any detail.
Data and Methodology
The data for this study come primarily from the 2002 American
Community Survey (ACS) collected by the U.S. Census Bureau. The survey contains
nearly 97,000 immigrants and is by far the largest survey collected that
includes a question on whether the respondent has given birth recently. It
should be noted that it also is possible to estimate fertility using the June
Current Population Survey (CPS) collected by the Census Bureau. However, the
American Community Survey contains seven times as many immigrants. Only the ACS
can be used to estimate fertility for immigrants from specific countries other
than the top one or two. Country-specific comparisons are necessary in order to
see if the fertility of immigrants differs from that of women in the countries
from which the immigrants came. The terms immigrant and foreign born are used
synonymously in this report. As the Census Bureau defines the term, the
foreign-born are persons living in the United States who were not U.S. citizens
The ACS is designed to replace the Census long form and includes as
many questions, including the respondent’s age, race, sex, and whether a person
is an immigrant and the country where each person was born. In addition, the
survey also asks women if they have given birth in the past year. This
information can be used to calculate what demographers call a Total Fertility
Rate (TFR) for the entire population or for a segment of the population. A TFR
is one of the most common measures of fertility used by demographers. It
represents the average number of children a woman will have in her lifetime once
she has passed through her reproductive years based on current trends.2 We
calculate TFRs for women ages 15 to 49. While there are a tiny number of births
to women younger than 15 and older than 49, the ACS does not capture births to
women outside of this range. It should be noted that TFR is designed to control
for differences in age structure between groups; thus if immigrants to the
United States are much younger or older than is the overall population of their
home country it should not unduly affect the findings of this study.
While we use the ACS to calculate immigrant fertility, there is
another way to calculate it. The National Center for Health Statistics (NCHS)
collects administrative data from birth certificates, and when this data is
combined with Census Bureau estimates of the total population, it can be used to
calculate TFRs. This is done by using the NCHS’s administrative data to report
the number of births to women in each age group and then dividing it by the
total number of women in that age group based on Census Bureau data, such as the
ACS. When dealing with immigrants, however, there are some disadvantages to this
approach. First the NCHS defines the foreign born somewhat differently than the
Census Bureau. Moreover, NCHS public use data only specifically identify three
countries (Mexico, Canada, and Cuba), while all other immigrant mothers are
simply reported as being foreign-born. Third, the ACS, like all Census Bureau
data, misses some fraction of the population; in contrast, the undercount in the
NCHS birth data is supposed to be very small.3 Thus,
combining administrative data with survey data like the ACS may tend to slightly
overstate immigrant fertility because the undercount in the ACS makes for a
denominator that may be too small.
Overall the ACS shows a TFR of
2.78 for all immigrant women ages 15 to 49. If we use the ACS in combination
with the NCHS birth data the TFR would be 2.91, hardly a huge difference.4 Of
course, it may be that the NCHS data combined with the ACS actually produces a
more accurate TFR for immigrants. But it must be remembered that this approach
uses two somewhat different data sources. Calculating a TFR using just the ACS
on the other hand avoids this problem because if there is an undercount of the
foreign born in the ACS, there is also an undercount of foreign-born women who
have given birth recently. It’s worth noting that most government publications,
but not all, calculate the nation’s TFR by using NCHS data combined with Census
Bureau data and not from just one survey like the ACS. For the purposes of this
study, the key point is that the differences between estimates of immigrant TFR
using either approach are small.5
Fertility in the Home
In order to compare immigrant fertility to that of their home
countries, we use the latest figures for TFRs from the United Nations Population
Division, Department of Economic and Social Affairs. The UN provides TFR for all
member states for the time period 2000 through 2005. We compare home country
fertility with the immigrants for the top-10 countries. We then weight the data
to reflect the share that immigrants from each of the countries accounted for in
the United States. Although the ACS is a very large survey, it is still not
large enough to calculate fertility for immigrants from countries other than the
top ten because the sample size for countries that send fewer immigrants is
quite small. Moreover, only a small fraction of women have children in any year.
By confining our analysis to the top countries, we are able to obtain more
statistically robust estimates of immigrant fertility. It should be pointed out
that the top-10 countries account for 58 percent of all immigrants in the United
States. Moreover, the total fertility for immigrants from the top countries in
2002 was 2.86, which is very similar to 2.78 for immigrants overall.
Immigrants and Their Countries.
When comparing immigrant fertility to that
of their home countries it is important to understand that immigrants can differ
in important ways from the general population of the countries from which they
come. It is probably not possible to control for all the ways in which
immigrants to the United States may be different from the general population
back home. While many factors impact fertility rates, it is a well-established
principle in demography that throughout the world education levels are a key
determinant of fertility, with more educated women having fewer children on
average than women with less education. The ACS can be used to estimate the
education level of immigrant women in the United States for the top sending
countries. We can then compare this to fertility rates by education level in
their home countries. Unfortunately, data for fertility by education levels for
foreign countries are not always as complete or detailed as we would like.6 Despite
these limitations, the available data can be used to adjust for the education
level of immigrants in the United States in most cases. Fertility figures by
education for the home countries come mainly from two sources: The Demographic
and Health Surveys provided by Macro International, Inc., and the Information &
Knowledge for Optimal Health Project at Johns Hopkins Bloomberg School of Public
Estimating Births to Illegal Aliens.
all Census Bureau surveys, the ACS includes individuals in the country
illegally. In fact, most researchers think about 90 percent of illegal aliens
are included in Census surveys. Therefore it is possible to estimate fertility
for illegals, or at least those illegals who respond to the ACS. Like almost all
researchers in this field, we use the characteristics of individuals in the ACS
to estimate the number of illegal immigrants. Based on the citizenship status,
year of arrival in the United States, age, country of birth, educational
attainment, sex, receipt of welfare programs, receipt of Social Security,
veteran status, and marital status reported in the ACS, we assign probabilities
to each survey respondent.8
This method is based on some
very well-established facts about the characteristics of the illegal population.
For example, it is well known that illegals are disproportionately young (under
age 40), male, unmarried, and have few years of schooling, etc. We estimate that
there were a total of 8.45 million illegal aliens in the 2002 ACS. We further
estimate that of illegal alien women ages 15 to 49, 58 percent are Mexican, and
21 percent are from other Latin America countries.
Fertility of Immigrants in the U.S.
Table 1 reports the TFR of immigrants
and their home countries. Overall, the figures show that immigrants in the U.S.
tend to have more children than do women in the countries form which they came.
Immigrants in the U.S. from these countries have a Total Fertility Rate of 2.86
in 2002, compared to 2.32 for women in their home countries — a 23-percent
difference. Put a different way, there are about 23 percent more children born
because of immigration to the United States, assuming that immigrants would have
had the same fertility of women in their home country. Table 1 indicates that
immigration to the United States does add to world population growth.
Individually immigrants from
seven of the top-10 countries have a higher TFR in the United States than in
their home countries. For those countries in which the immigrants have higher
fertility, the biggest differences are for women from Mexico and China. Mexico
is especially important because immigrants from that country account for more
than 40 percent of all births to immigrants and 54 percent of births among the
top-10 immigrant-sending countries in Table 1. Thus immigrants from that country
exert a very significant impact on the results. While immigrants from the
top-sending countries tend to have more children than women in their home
counties, this is not true in every case; the Philippines, India, and Viet Nam
are the exceptions.
of Home Countries?
Table 1 compares immigrants to those in their home
countries. As discussed in the Data and Methodology section of this report,
immigrants to the United States can differ in important ways from people in
their home countries. Throughout the world, a key determinant of how many
children a woman will bear in her lifetime is her education level. In almost
every country in the world, more educated women have significantly fewer
children than women with less education. If immigrants to the United States have
a different educational profile than the general population of their home
countries, then it can have a significant impact on fertility. Table 2 attempts
to adjust for at least some of these differences.
To understand why adjusting
for education level is necessary, consider the case of India. Although overall
fertility in that country is 3.1, a 1998-99 survey found fertility in that
country varies from 3.5 children for women with no education to 2.0 for women
who have completed secondary school. The 2002 ACS shows that 90 percent of
female Indian immigrants in the United States have completed secondary school.
If Indian women in the United States had the same fertility rate as women in
India with the same education level, then their fertility rate would have been
2.19. This is very similar to the 2.23 children the ACS shows is its actual
fertility. Thus all of the difference between the fertility of women in India
and Indian immigrants in the United States found in Table 1 disappears when we
account for the education level of immigrants from that country.
Overall Table 2 shows that the
difference between home countries and their immigrants in the United States is
actually larger when we control for education. The table shows that immigrants
from the top-10 sending countries should have 2.15 children on average, which is
33 percent less than their actual fertility. In the cases of India and Vietnam,
where the straight comparison in Table 1 seemed to show that immigrants in the
United States have lower fertility than women in their home countries, the
fertility in the United States actually is about the same as back home once we
control for education levels. For China and Mexico, the difference actually
widens with the home country. Only in the case of the Philippines do immigrants
seem to have fewer children in the United States and the difference does not
seem to narrow even when we control for the mother’s education level. The
Philippines might be a special case, because such a large share of Filipino
women are married to American servicemen and have high marriage rates to
native-born Americans in general. Therefore, their child bearing may reflect the
preferences for small families common among Americans. In any event, Table 2
shows that, at least when we account for education levels, immigrants from the
top-sending countries tend to have significantly more children than women in the
countries from which they come. Of course, comparisons of this kind are by no
means perfect, but they at least allow us to account for some of the differences
between immigrants in the United States and the countries they come from.
Estimated Fertility of
We estimated that the fertility of illegal aliens in 2002
was 3.06 children on average, or about half again as high as the fertility rate
for natives. This compared to an estimated 2.61 for legal immigrants. In a study
released in July of this year, we used birth certificate records and estimated
that in total there were 380,000 births to illegal aliens in 2002, accounting
for nearly one out of every 10 births in the United States. The high fertility
rate of illegal aliens seems to be due primarily to factors other than their
legal status, such as culture and educational attainment. It must be remembered
that some 80 percent of the illegal population is from Latin America, and more
than 60 percent lack a high school degree. Because the fertility of illegals is
very similar to Hispanic immigrants in general, it suggests that illegals are
not purposefully having children, who are automatically awarded US citizenship,
in order to remain in the United States.
The large number of births to
illegals is important for a number of reasons. Perhaps most importantly, it
shows that the longer illegal immigration is allowed to persist, the harder the
problem is to solve. As U.S. citizens, these children can remain permanently,
and their citizenship can effectively prevent a parent’s deportation. Moreover,
once adults they can sponsor their parents for permanent residence. Births to
illegals also have significant bearing on U.S. population growth. If illegal
aliens are allowed to remain in the country, either as illegal aliens or as
legal residents, their births alone will add some four million people to the
U.S. population over the next decade.
Fertility by Education
As already discussed, education is one of the key determinants of
fertility. One reason fertility rates have declined so much around the world in
recent decades is that the education level for women has increased significantly
in almost every country. Table 3 reports the fertility for immigrant and native
women based on their education level. It confirms the basic fact that fertility
tends to vary with education levels. But it also shows that, relative to
natives, the differences between well-educated and less-educated immigrants are
very large. For example, at 3.3 and 3.4 children, the fertility of immigrants
without a high school degree or only a high school degree is three-fourths
higher than the 2.0 and 1.9 rates for immigrants with some college or college
graduates. In contrast, the 2.3 rate for natives without a high school or with
only a high degree is not that different than the 1.8 rate for more educated
The higher fertility of
less-educated immigrants means that a much larger share of births to immigrants
are to women with little formal education than is the case for natives. This is
important because education is the best predictor of income, poverty, use of
means-tested programs, and a host of other measures of social well being. For
the children of immigrants it means that a very large share may grow up poor.
These findings also have implications for likely educational attainment of the
children of immigrants. Those born to less educated parents are themselves at
higher risk for dropping out of high school. In addition to the cost to
taxpayers, the results in Table 3 indicate that many children from immigrant
families may have significant difficulty in reaching economic and social parity
with the children of natives. Many researchers simply examine the education
level of immigrants and natives. But examinations of this kind might be
misleading when thinking about future generations because the number of children
born to immigrants is not proportionate to the size of each educational group.
When thinking about the second generation, it is important to realize that the
children of less educated immigrants will comprise a large share of births, a
share that is significantly larger than would be expected if one simply assumes
that all immigrants have the same fertility.
Immigrants Do Not Account
for High U.S. Fertility.
In a study in April of this year, we found that
immigrants had little impact on the nation’s fertility.9 Using
a different data source, we found that without immigrants the national fertility
rate still would be two children on average. The 2002 ACS study shows the same
basic results. If all the immigrants are removed from the data and the fertility
rate recalculated, the overall fertility rates in the United States would still
be about two children, or 2.05 children. It is true that America does have a
higher fertility rate than other advanced industrialized democracies – 1.4 for
Europe or 1.3 for Japan. But that higher rate is due almost entirely to
native-born American women. For whatever reason, they have significantly more
children on average than women in other western countries. It must be remembered
that nearly eight out of 10 births in the United States are to native mothers,
thus it is their characteristics that will primarily determine the overall
fertility rate in the United States.
Immigration Accounts for
Most U.S. Population Growth.
Although immigration has little effect on the
nation’s overall fertility rate, new immigrants (legal and illegal) plus births
to immigrants add some 2.3 million people to the United States each year,
accounting for most of the nation’s population increase. In fact, because
natives have only two children on average, absent the additions that come from
immigrants, the U.S. population would be roughly stable in the long-run without
continued high levels of immigration. Whatever one thinks about the costs and
benefits of continued population growth, there is no question that immigration
is the driving force behind it.
The overall findings of this
study indicate that immigrants from the top sending countries tend to have more
children than they would have been had they remained in their home countries.
Analysis of the 2002 American Community Survey shows that, on average,
immigrants from the top-10 sending countries have 23 percent more children in
the United States than women in the countries from which they come. When we
adjust for the fact that immigrants in the United States tend to be more
educated than the general population of their home countries, the difference in
fertility tends to grow to 33 percent. It is not clear why immigrants tend to
have more children than in the countries from which they come. Perhaps it is due
to the fact that immigrants feel more prosperous once here and as a result
decide they can have another child. There is certainly strong evidence that
immigrants realize substantial economic gains by coming to the United States.
We also estimate that illegal-alien
women had slightly less than 3.1 children on average in 2002, or about 50
percent higher than the two children natives have on average. The birth rate for
legal immigrants is 2.6, or about one-third higher than that of natives. We have
previously estimated from birth records that there were 380,000 births to
illegal aliens in 2002, accounting for nearly one out of 10 of all births in the
United States. The high fertility rate of illegal aliens seems to be due
primarily to factors other than their legal status, such as culture and
The children born to immigrants are
arguably the most important long-term legacy of immigration. The decision to
have children is one of the most important any woman makes in her lifetime. The
fact that immigrants tend to have more children once they come to the United
States than do their counterparts in their home countries is an important
finding. While the demographic data on which this study is based are clear, the
reason for the finding is not. Perhaps it results from a feeling of optimism
about the future immigrants experience after coming to America; perhaps it is
the assistance the government offers to low-income women with children; or maybe
it has something to do with the way immigrants differ from the populations of
their home countries. These and other possible explanations are all areas in
need of further research.
includes persons who are naturalized American citizens, legal permanent
residents (green card holders), illegal aliens, and people living in the United
States on long-term temporary visas such as students or guest workers. The
Census Bureau definition does not include those born abroad of American citizen
parents. As we will see, other government agencies do consider persons born
abroad to U.S. citizen parents as foreign-born.
Arthur Haupt and Thomas Kane have defined TFR as, “the average number of
children that would be born alive to a woman (or group of women) during her
lifetime if she were to pass through all her childbearing years conforming to
the age-specific fertility rates of the given year.” All demographics textbooks
provide a discussion of TFR; see for example David Yaukey and Douglas L.
Anderton, “Demography: The Study of Human Population,” 2001. Waveland Press, pp.
3. The NCHS reports
that more than 99 percent of births in the United States are recorded. See
“National Vital Statistics, Births: Final Data 2002,” Vol. 52 number 10, page 3.
4. It should be
noted that the TFR of 2.91 is based on ACS and NCHS data and includes persons
born aboard of American parents. This is true both for the NCHS birth data and
the ACS population totals which are used as a denominator. Although the children
of American citizens born in other countries are technically not immigrants and
are not considered foreign born by the Census Bureau, they are counted as such
in NCHS data.
5. It should be
noted that using the 2002 June CPS, the TFR for foreign-born women was 2.4. This
is quite a bit larger than the 2.8 TFR shown in the ACS and 2.9 using NCHS data.
Sampling variability accounts for most of this difference; using a 95 confidence
interval, the ACS and CPS are barely statistically different. Moreover, the
question wording of the two surveys is not the same. Finally we use the ACS to
measure fertility up to age 49, while the CPS does not question older women
about their recent child bearing experience. One of the big differences between
the two surveys is that the ACS reports some 860,00 births to immigrants while
the CPS records only 630,000. It is not clear why there is the large difference,
but the NCHS data, which is based on actual birth records from hospitals, shows
900,000 births to foreign born mothers (using the NCHS definition of
foreign-born) in 2002. Thus the ACS seems to produce estimates that more closely
match births figures from administrative data than does the CPS. This gives us
more confidences in the ACS results.
6. In some cases
the available data are relatively old and in other cases the education
categorizes are highly aggregated.
7. Figures for
fertility by education from the Demographic and Health Surveys can be found at <
http://www.measuredhs.com/contact.cfm >. Fertility data by education level
from the Johns Hopkins School of Public Health can be found at < www.infoforhealth.org
>, see Table B.
For China we use a 2000 paper by Cao Gui-Ying, which can be found at <
www.iiasa.ac.at/Publications/Documents/IR-00-026.pdf >. For Mexico we use the
data from the National Population Council of Mexico, which can be found at < www.conapo.gob.mx
>. In the case of
Mexico, China, India, and El Salvador the data for home country fertility by
education is older than we would like, so we adjusted it to reflect the UN’s
2000-05 fertility estimates assuming that fertility changed between the time of
the survey and 2002 for each educational group in the same proportion as for the
overall fertility rate. Because fertility is already so low for Cuba, Korea,
Canada, and the United Kingdom, we did not adjust for the education level of
those immigrants in the United States. If we had done so it would have probably
increased the difference with home countries in each case because immigrants in
the United States tend to be more educated than the general population of the
home country. But any effect would be very small. One limitation of the data for
the six countries that we did adjust is that in some cases the educational
categories are quite aggregated. For example, for the Demographic and Health
Surveys there are only three categorizes: 1) those with no education; 2) those
with a primary education; 3) those with a secondary or higher education. Many
immigrants to the U.S. are very educated, and this fact is lost because of the
way the surveys group more educated women. If we had been able to find figures
for fertility by education level in the home countries for more highly educated
women it almost certainly would have further increased the gap with the home
countries found in tables 1 and 2.
individuals who have a cumulative probability of 1 or higher are assumed to be
illegal aliens. By design, the probabilities are assigned so that both the total
number of illegal aliens and the characteristics of the illegal population
closely match other research in the field, particularly the estimates developed
by Jeffery Passel, formerly of the Urban Institute, now at the Pew Hispanic
9. “Immigration in
an Aging Society: Workers, Birth Rates, and Social Security,” <
Dr. Steven A. Camarota is the Director of Research at the
Center for Immigration Studies.
Courtesy of the Center for Immigration Studies.
Mark Krikorian, Executive Director
Center for Immigration Studies
1522 K Street N.W., Suite 820
Washington, DC 20005
See original at < http://www.cis.org/articles/2005/back1105.html >.