NCHS Data Brief ■ No. 68 ■ August 2011

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

Childbearing Differences Among Three Generations of 

U.S. Women 

Sharon E. Kirmeyer, Ph.D.; and Brady E. Hamilton, Ph.D.

Key findings

• Of three generations of 

women born in 1910, 1935, and 

1960, those born in 1935 had 

the most children (on average 

3.0 children per woman) and 

those born in 1960 had the 

fewest (2.0).

• Women born in 1910 and 

1935 started their childbearing 

at the youngest ages with an 

“average” or median age at first 

birth of 21 years; more than 

70 percent of their first births 

occurred to women under age 

25. The median age at first birth 

was oldest for the 1960 birth 

cohort (23 years). 

• Thirty-seven percent of 

women born in 1935 had four 

or more children; women born 

in 1960 were the most likely to 

have two children (35 percent); 

and women born in 1910 were 

equally likely to have no, one, 

or two children (approximately 

22 percent each). 

• Of these three cohorts, 

women born in 1910 were the 

most likely to be childless by 

age 50 (20 percent), whereas 

those born in 1935 were the 

least likely (11 percent).

Each year a generation of women is born who will share similar sociohistorical 

experiences before and throughout their reproductive lives. These unique 

experiences can produce similar childbearing patterns in terms of the average 

number of children ever born—whether mothers are younger or older when their 

first birth occurs and the proportion of women who do not have children—that 

can differ from the patterns found for other cohorts. Childbearing patterns have 

profound consequences for society. These consequences include the demand 

for schools and housing, as well as women’s participation in the labor force. 

Moreover, the lives of women who become mothers are significantly different 

from those who do not. Having children affects the acquisition of material goods 

and may impose costs for the mother in terms of personal and professional 

options. This report presents data on three selected birth cohorts of women 

representing generations born at 25-year intervals in 1910, 1935, and 1960, close 

to the average length of a generation in the United States (1). Data are from the 

cohort fertility tables, based on the National Vital Statistics System.

Keywords: birth cohort • childlessness • total fertility rate

Women born in 1935 had on average three births—the 

highest of the three cohorts. Births per woman

Year cohort completed fertility

1910 cohort:

2.4

1935 cohort:

3.0

1960 cohort

(estimated):

2.0 

NOTE: Based on total fertility rates for women aged 45–49. 

SOURCE: CDC/NCHS, National Vital Statistics System.

Figure 1. Cohort total fertility rates: United States, 1950–2005

0.0

1.5

2.0

2.5

3.0

3.5

2005

2007

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
NCHS Data Brief ■ No. 68 ■ August 2011

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• The total fertility rate (TFR) for the 1935 birth cohort— that is, the “average” number of 

children per woman—was 3.0 (Figure 1), the highest of the three cohorts. In contrast, the 

lowest number was 2.0 children per woman born in 1960. The TFR of women born in 1910 

was between these rates at 2.4.

• These three generations of women achieved their completed fertility close to the lowest and 

highest levels of the cohorts that completed their childbearing in the last half-century. The 

TFRs peaked at 3.2 children per woman in 1980 for the 1931–1935 cohort and troughed at 

2.0 children per woman in 2002 for the 1953–1957 cohort.

Women born in 1960 started their childbearing at an older age.

• Nearly three-quarters of the first births born to members of the 1910 and 1935 cohorts 

occurred when the cohort was under age 25, compared with one-half of the births to mothers 

in the 1960 cohort.

• For women born in 1910 and 1935, having a first birth after age 30 was relatively rare (less 

than 10 percent of births) compared with close to 20 percent of births occurring to mothers 

born in 1960.

• Women born in 1935 had the lowest “average” (median) age at first birth (20.8 years) (2). 

The highest median age was 22.7 for women born in 1960 (Figure 2). The 1910 cohort was 

between the other two cohorts, with a median age at first birth of 21.1.

NOTE: Access data table for Figure 2 at: http://www.cdc.gov/nchs/data/databriefs/db68_tables.pdf#2.

SOURCE: CDC/NCHS, National Vital Statistics System.

0

20

40

60

80

100

30–49 years

25–29 years

20–24 years

15–19 years

1910 1935 1960

Percent

Birth cohort year

Figure 2. Age of mother at first birth, by birth cohort of mother: United States, 1910,1935, and 1960
NCHS Data Brief ■ No. 68 ■ August 2011

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Women born in 1935 had the highest number of children; women born in 

1910 had the fewest children.

• Women born in 1935 tended to have larger families, with four or more children being the 

most frequent outcome (37 percent) (Figure 3). 

• Women in the 1910 cohort were equally likely to have no, one, or two children 

(approximately 22 percent each) of the birth outcomes of that group.

• For women born in 1960, two births per family was most common (35 percent). They were 

the least likely of the three cohorts to have four or more births.

NOTE: Access data table for Figure 3 at: http://www.cdc.gov/nchs/data/databriefs/db68_tables.pdf#3.

SOURCE: CDC/NCHS, National Vital Statistics System. Percent

Number of children

0

10

20

30

40 1910 cohort 1935 cohort 1960 cohort

0 1 2 3 4 or more

Figure 3. Percent distribution of the number of children ever born, by birth cohort of mother: United States, 1910, 1935, 

and 1960
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Women born in 1910 were almost twice as likely to be childless as women 

born in 1935.

• At age 50, the percentages of childless women in the selected birth cohorts were 19.7 

percent for women born in 1910, 11.4 percent for women born in 1935, and 15.6 percent for 

women born in 1960 (Figure 4). 

• While differences in the proportions childless in the three cohorts were essentially constant 

for ages 40 and over, this was not true at earlier ages. Women born in 1960 postponed their 

first births longer and were more likely to be childless in their 20s and early 30s compared 

with the other two cohorts. After age 40, the percentage childless for this cohort was 

between the levels for the cohorts of 1910 and 1935. 

SOURCE: CDC/NCHS, National Vital Statistics System.

Age in years

Percent

0

20

40

60

80

100

1960 cohort

1935 cohort

1910 cohort

15 20 25 30 35 40 45 49

Figure 4. Percentage of women childless, by age and birth cohort of mother: United States, 1910, 1935, and 1960
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Summary

Women born in 1910 had the highest proportion of childlessness and a corresponding low TFR. 

In contrast, women born in 1935 had both the lowest proportion of childlessness and the highest 

TFR. The fertility of women born in 1960 is characterized as generally between the two earlier 

cohorts in terms of childlessness, but is distinct with both the smallest average family size and 

the oldest age at first birth. First-time childbearing is more concentrated among younger women 

for the 1910 and 1935 cohorts than for the 1960 cohort. Finally, for all three cohorts, at least 80 

percent of women had a child by age 40.

These distinct fertility patterns were a product of sociohistorical forces during these generations’ 

reproductive lives. The childbearing of the earliest cohort (1910) was largely affected by the 

Great Depression and World War II. The drop in marriages and uncertainty brought by those 

events lowered the likelihood of childbearing (3). Women in the middle cohort (1935) started 

their reproductive lives after the end of the World War II when the number of marriages jumped, 

and the economy prospered (4). For a number of reasons, including the increases in women’s 

educational and occupational opportunities (5) and availability of reliable means of fertility 

control (6), the fertility of the last cohort (1960) was delayed and resulted in a smaller family size 

than that of the two earlier cohorts.

Definitions

Birth cohort: Refers to a group of women born in the same year. 

Childlessness: Refers to the state of women who have not given birth to live-born infants.

Completed total fertility rate (or “average family size”): Refers to the number of births that a 

cohort of women had at the end of their childbearing years, usually expressed as the average 

number of children per woman, but alternatively expressed as the average number of children per 

1,000 women. It is the sum of fertility rates over all ages in a birth cohort.

Average (or median) age at first birth: Refers to the point that separates the younger one-half

(50 percent) of women who are having a first birth from the older one-half.
NCHS Data Brief ■ No. 68 ■ August 2011

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Data sources and methods

Data shown in this report are based on the Natality Data Files of the National Vital Statistics 

System. The vital statistics natality file includes information for all births occurring in the 

United States and covers a wide range of maternal and infant demographic and health 

characteristics. Population data for computing the rates were provided by the U.S. Census Bureau.

The sources for the information used in this report are “Transitions Between Childlessness and 

First Birth: Three Generations of U.S. Women,” “Fertility Tables for Birth Cohorts by Color: 

United States, 1917–1973,” “Cohort Fertility Tables for All, White, and Black Women: 

United States, 1960–2005,” and annual cohort fertility tables in the 1974 and 1999 Vital Statistics 

of the United States (2,7–10). Information on the cohort fertility tables and measures presented in 

this report is available elsewhere (2,7,8).

About the authors

Sharon E. Kirmeyer and Brady E. Hamilton are with the Centers for Disease Control and 

Prevention’s National Center for Health Statistics, Division of Vital Statistics, Reproductive 

Statistics Branch. 
NCHS Data Brief ■ No. 68 ■ August 2011

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References

1. Preston SH, Heuveline P, Guillot M. Demography: Measuring and modeling population 

processes. Oxford, UK: Blackwell Publishers Ltd. 2001.

2. Kirmeyer SE, Hamilton BE. Transitions between childlessness and first birth: Three 

generations of U.S. women. National Center for Health Statistics. Vital Health Stat 2(153). 2011.

3. Glick PC. A demographer looks at American families. J Marriage Fam 37(1):15–26. 1975.

4. Petersen W. Population, 3rd Edition. London, UK: Macmillan Publishing Company, Inc. 1975.

5. Bureau of Labor Statistics. Changes in men’s and women’s labor force participation rates. 

The Editor’s Desk. Washington, DC: U.S. Department of Labor. 2007.

6. Mosher WD, Westoff CF. Trends in contraceptive practice: United States, 1965–76. National 

Center for Health Statistics. Vital Health Stat 23(10). 1982.

7. Heuser RL. Fertility tables for birth cohorts by color: United States, 1917–1973. DHEW 

Publication No. 76–1152. Rockville, MD: National Center for Health Statistics. 1976.

8. Hamilton BE, Cosgrove CM. Cohort fertility tables for all, white, and black women: United 

States, 1960–2005. Internet tables. Hyattsville, MD: National Center for Health Statistics. 2010. 

9. National Center for Health Statistics. Vital statistics of the United States, 1974. Volume 1, 

Natality. 1978.

10. National Center for Health Statistics. Vital statistics of the United States, 1999. Volume 1, 

Natality. 2001.
NCHS Data Brief ■ No. 68 ■ August 2011

Suggested citation

Kirmeyer SE, Hamilton BE. Childbearing 

differences among three generations of 

U.S. women. NCHS data brief, no 68. 

Hyattsville, MD: National Center for Health 

Statistics. 2011.

Copyright information

All material appearing in this report is in 

the public domain and may be reproduced 

or copied without permission; citation as to 

source, however, is appreciated.

National Center for Health 

Statistics

Edward J. Sondik, Ph.D., Director

Jennifer H. Madans, Ph.D., Associate 

Director for Science

Division of Vital Statistics

Charles J. Rothwell, M.S., Director

U.S. DEPARTMENT OF

HEALTH & HUMAN SERVICES

Centers for Disease Control and Prevention

National Center for Health Statistics

3311 Toledo Road

Hyattsville, MD 20782

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