1. Main points

  • The average completed family size for women born in 1969, and reaching age 45 in 2014, was 1.91 children per woman. This compares with their mothers’ generation, represented by women born in 1942, who had 2.29 children on average

  • Two children was the most common family size for women born in both 1942 and 1969

  • The level of childlessness among women born in 1969 (18%) is higher than for women born in 1942 (11%). One in 10 women born in 1969 had 4 or more children, compared with around 1 in 6 women born in 1942

  • Women born in 1984 – the most recent cohort to reach age 30 - have had slightly fewer children on average (1.02) by their 30th birthday than women born in 1969 who had 1.12 children by the same age

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2. Introduction

This release previously called "Cohort Fertility" was renamed as “Childbearing for women born in different years” in 2013 and presents statistics on childbearing among women in England and Wales. These figures are presented by the year of birth of mother – for groups of women born in the same year - rather than by the year of birth of child. The estimates have been updated with 2014 births, the latest data available, which means that completed family size for women born in 1969 (women reaching age 45 in 2014) is presented for the first time. Although the release is now called “Childbearing for women born in different years” we shall be using the word “cohort” at places within the text for simplicity. A cohort in this statistical bulletin is a technical word to describe a group of women born in the same year.

This statistical bulletin provides supporting commentary for the release, which includes data tables on:

  1. average number of live-born children by age and year of birth of woman, 1920 to 1999

  2. proportion of women who have had at least one live birth, by age and year of birth of woman, 1920 to 1999 - the proportion of women who have not had children (see childlessness definition) is also shown in this table

  3. percentage distribution of women of childbearing age by number of live-born children, by age and year of birth of woman, 1920 to 1995

  4. age-specific fertility rates by age and year of birth of woman, 1920 to 1999

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3. What is cohort fertility?

A cohort is a group of people having experienced a particular event (birth or marriage, for example) during the same period. In this bulletin birth is the event considered; therefore the cohort will be called a birth cohort, for example, the 1984 female birth cohort will refer to all women born during the year 1984 in England and Wales.

Cohort fertility analyses explore whether current generations of women of childbearing age are reaching, exceeding or falling short of the fertility levels of previous generations. This bulletin contains statistics on changes in average family size for past and present cohorts, levels of childlessness for different cohorts of women and the proportions of women having 1, 2 or more children.

The main cohort presented here is women born in 1969, who were aged 45 in 2014. This is the most recent cohort that is assumed to have completed their childbearing1. This statistical bulletin compares the completed family size of women born in 1969 with that of their mothers’ generation; the average age of mothers giving birth in 1969 was 27 years and women of that age were assumed to be born in 1942.

Women born in 1984, who have reached age 30 in 2014, are also used as a comparison group, as age 302 may be considered the mid-point of a woman’s childbearing years which are assumed to start at age 15 and end at the age 45. This bulletin compares the achieved fertility of the 1984 cohort by this age with that of previous cohorts by the same age.

Notes for what is cohort fertility?

  1. A woman is assumed to have completed her childbearing by the last day she is aged 45, that is by her 46th birthday (exact age 46). Completed fertility includes fertility rates up to and including age 45. See background note 4 for a more technical explanation

  2. The ages of women are presented in 'exact years'. Therefore figures should be interpreted as the average number of children a woman has had up to that birthday. So childbearing up to exact age 30 includes cumulative fertility through her lifetime up to the day before her 30th birthday. Any childbearing in the 12 months from her 29th birthday onwards will be included in fertility up to exact age 30. See background note 4 for a more technical explanation

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4. Main figures

Table A shows the average family size and estimated family size distribution for women who have completed their childbearing years in 2014 and of the cohort assumed to be their mothers. The 1942 cohort is assumed to be their mothers' generation because the average age of mothers giving birth in 1969 was 27 years and so women of that age were assumed to be born in 1942.

This comparison of the most recent cohort to have finished their childbearing with their mothers' cohort lets us examine change over time. The completed family size of the 1969 cohort is much smaller than for the 1942 cohort and the proportion of women remaining childless is substantially higher for the 1969 cohort.

Changing family size

This interactive application allows you to engage with “Childbearing for women born in different years” and explore how women born in the same year as you compare to women born in the same year as your mother.

Average family size

Figure 1 shows the average number of live-born children (completed family size) for women who are assumed to have completed their childbearing. This is a cumulative measure derived from summing the fertility rates of female birth cohorts at each age from 15 to 45 and over. The most recent cohort to complete their childbearing (women born in 1969) had on average 1.91 children, similar to recent previous 3 cohorts (1965 to 1967). Average completed family size peaked at 2.42 children for women born in 1935, and has been falling since. Women belonging to the 1958 cohort were the first estimated to have an average completed family size of fewer than 2 children over their childbearing lifetime. This decrease in the average family size is mainly due to rising levels of childlessness, which is discussed further in the next section.

Figure 1 also shows the average number of live-born children for women by their 30th birthday.

The average number of children women have had up to their 30th birthday can give an indication of more recent trends in family size. Figure 1 shows a slight upturn in average family size by the 30th birthday for the most recent cohorts, from 0.98 children for the 1978 cohort to 1.02 for the 1984 cohort. This is mainly because women born in 1984 had higher fertility rates in their late twenties than those born in 1978. There is no single explanation for this increase, but possible reasons include the changes in support for families introduced by previous governments (such as tax credits and maternity or paternity leave)1 and the increasing proportion of women aged 25-29 who were born outside the UK (with fertility above the UK born average)2.

Overall, women born in the 1960s and 1970s have had fewer children by age 30 than previous generations. The 1969 cohort had 1.12 children on average by their 30th birthday, compared with 1.86 by the same age for their mother’s generation, the 1942 cohort. This reflects their postponement of childbearing to older ages, for reasons including:

  • increased participation in higher education3

  • delayed marriage and partnership formation1

  • the desire to establish a career, get on the housing ladder and ensure financial stability before starting a family1

Notes for main figures

  1. Jefferies, J (2008), Fertility assumptions for the 2006-based national population projections, Population Trends, no 131, pp 18-27

  2. Zumpe, J, Dormon, O, and Jefferies, J (2012) Childbearing among UK born and non-UK born women living in the UK. Office for National Statistics

    Dormon, O (2014) Childbearing of UK and non-UK born women living in the UK, 2011 Census data. Office for National Statistics

  3. Ni, Bhrolchain, M, Beaujouan, E (2012) Fertility postponement is largely due to rising educational enrolment, Population Studies, Volume 66, issue 3, pp. 311-327

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5. Childlessness

Childlessness is defined as the condition of being without children. There are 2 distinguishable types of childlessness, voluntary and involuntary. The difference between the 2 is mostly self-defined. Voluntary childlessness, also described as childfree, child-free, childless by choice or childfree by choice1, relates to women who have chosen not to have children. Involuntary childlessness relates to women who are without a child because of circumstance or biology rather than choice.

We publish data on all childless women, whether by circumstance or by choice. This is in line with the United Nations definition of childlessness2:

  1. "Childless by Choice Project"

  2. United Nations World Fertility Report 2009

Childlessness is estimated as the proportion of women who have not had a live birth by a specific age.

Figure 2 shows that the level of childlessness at age 45 for women born in 1969, is relatively high compared to their mother’s cohort at 18%, but slightly lower than for the 1967 cohort (19%) and the previous 6 cohorts, which had 20% childlessness each. Around 1 in 5 women born in 1969 remained childless by the end of their childbearing years compared with 1 in 9 women born in 1942. However, late 1960s levels are not new; they are comparable to early 1920s levels. A wide range of explanations relating to circumstances and choices have been put forward for the increasing childlessness seen in recent cohorts. These include the decline in the proportion of women married, changes in the perceived costs and benefits of childrearing versus work and leisure activities, greater social acceptability of the childfree lifestyle and the postponement of decisions about whether to have children until it may be biologically too late1.

On their 30th birthday, 47% of the 1984 cohort were childless, a higher proportion than for the 1969 cohort at the same age (43%). This highlights the trend that women have been increasingly delaying having children to older ages. However, Figure 2 shows that while the proportion of women childless by age 30 increased slightly for women born in 1984, prior to that it had been falling for successive cohorts born from 1975 to 1982 (when 48% of women had not yet had a live birth by age 30). However, it is too early to say whether this new upward trend will continue.

Notes for childlessness

  1. For reasons for increasing childlessness, see for example:

    • O'Leary L, Natamba E, Jefferies J and Wilson, B (2010) Fertility and partnership status in the last two decades, Population Trends 140, page 5-35
    • Simpson, R (2009) Delayed childbearing and childlessness in Britain, in Stillwell, J, Kneale, D and Coast, E (eds.) Fertility, Living Arrangements, Care and Mobility: Understanding Population Trends and Processes Volume 1, Springer, Dordrecht, pp. 23-40
    • Basten, S (2009). Voluntary childlessness and being Childfree. The Future of Human Reproduction: Working Paper #5
    • Berrington, A.M. (2004). Perpetual postponers? Women's, men's and couple's fertility intentions and subsequent fertility behaviour. Population Trends 117: 9-19
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6. Teenage childbearing

Figure 3 shows that the proportion of women who have a child by age 20 has been gradually decreasing for recent cohorts. From a peak of around 1 in 5 for women born in 1952, it has declined to 1 in 12 women for those born in 1994, the most recent cohort to reach age 20. This shows that the proportion of women becoming teenage mothers is falling, though the level of teenage motherhood remains slightly above that of the cohorts born in the early 1920s when around 7% of women had a child by age 20. This fall in the proportion of teenagers becoming mothers has accompanied recent falls in the annual number of teenage conceptions.

Conception statistics include all pregnancies of women usually resident in England and Wales which lead to either a live birth, still birth or an abortion under the 1967 Abortion Act. The most recent figures on under-18 conception rates for England and Wales show that in 2013 the rate was 24.5 conceptions per thousand women aged 15 to 17, which is the lowest level since records began in 1969 (a decrease of over 40% since then)1. Teenage conception and birth rates are used widely as outcome indicators in the sexual health context1.

Notes for teenage childbearing

  1. More details on teenage conceptions can be found in our annual conceptions release:

    Conception Statistics, England and Wales

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7. Number of children

The traditional 2-child family remains the most common family type in England and Wales, with 37% of women born in 1969 having 2 children (Figure 4, Table B). Families with none or 3 children are equally second most common at 18% each of the total for the 1969 cohort. The proportion of families with 1 child has increased over time to 17%, equal with the 1968 cohort and a level not previously seen since the 1932 cohort.

Table B shows the family sizes of women who are assumed to have completed their childbearing.

The latest cohort to complete their childbearing were those women born in 1969, who were aged 45 in 2014. Of this cohort roughly 18 percent remained childless. This compares with the 1945 cohort where only approximately 10 percent of women remained childless.

17% of women completing their childbearing in 2014 had 1 child, continuing a rise over the last few years from 13% in the 1965 cohort. One child families were more common among women born in the 1920s and 1930s, where as many as 22% had 1 child. Of the cohorts of women born in the 1940s, 10 to 14% had 1 child by the age of 45, slightly lower levels than for women completing childbearing in 2014.

Two children has remained the most popular family size. After peaking around 1950, with 44% of women having two children, it stabilised at 38% for cohorts born through the 1960s before declining slightly to 37% for the 1967-69 cohorts.

A woman born in 1940 was more likely to have 1, 3 or, ‘4 or more’ children than not to have any. Only one in ten women born in 1969 had four or more children, compared with nearly 1 in 5 in the 1940 cohort (Table B).

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8. The changing age pattern of fertility

The fertility rates of selected cohorts at particular age milestones highlight how the age distribution of women giving birth has changed over time. As an example, the 2 vertical lines on Figure 5 allow a comparison of the age profile of fertility in the 1969 cohort (who have completed their childbearing), their mothers’ generation (cohort of 1942) and that of the 1984 cohort to date. The fertility rates for women at ages 20, 25, 30, 35 and 40 have been chosen for illustration here (Figure 5), but equally any age or selection of ages could be charted.

For the 1969 cohort, the highest fertility rate of those shown was at the age of 30, closely followed by age 25. Lower levels of fertility were recorded at ages 20 and 35, while the number of live births per 1,000 women at the age of 40 was lower still. On average, the 1969 cohort reached 1.91 children per woman. In comparison with the 1942 cohort, the 1969 cohort had much lower fertility at ages 20 and 25, though at age 30 fertility rates were similar. At older ages, the 1969 generation had higher fertility, as shown at ages 35 and 40 (Figure 5). However, this recuperation at older ages was not sufficient to catch up with the larger completed family size of the 1942 cohort who had 2.29 children per woman on average.

Age-specific fertility rates for the 1984 cohort are currently only available up to the age of 30. For this cohort, fertility rates at age 30 were a little higher than for the 1969 cohort but decreased slightly from the level experienced by the 1982 cohort. In contrast, fertility rates at age 20 were slightly lower than seen in the 1969 cohort, while at the age of 25 they were much lower for the 1984 cohort than for the 1969 cohort.

Fertility at age 25 hit a low for women born in 1977 before rising slightly among cohorts born between 1978 and 1987. Women born in 1984 had 12% fewer live births per 1,000 women at age 25 than women born in 1969.

If recent trends in childbearing at older ages continue, the 1984 cohort would be expected to have an older average age at childbearing than the 1969 cohort.

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9. Uses of birth statistics

We use birth statistics to:

  • produce mid-year population estimates and population projections, both national and subnational

  • quality assure census estimates

  • report on social and demographic trends

Other main users of birth statistics include the Department for Education and the Department of Health, academics, demographers, health researchers, lobby groups, international organisations and the media.

We use Cohort fertility statistics and estimates of fertility by family size for producing the fertility component of population projections and for reporting on social and demographic trends. They are also of important interest to academics researching changing family building patterns over time.

The Department for Work and Pensions uses information on family size for modelling future lone parents, pensions and benefits.

Estimates of childlessness are of interest to policymakers concerned with the support and care available to people at older ages. Estimates of family size are of use to special interest groups such as organisations and networks supporting large families and for people who are, or who have, an only child.

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10 .Further information

Cohort fertility figures in this release are based on all live births registered in England and Wales. However, due to the method of estimating true birth order up to 2012 for certain tables (see data sources and changes to data section), these figures cannot be disaggregated separately for England only and Wales only, nor produced for males.

For information on data quality, legislation and procedures relating to birth statistics please see Births Metadata (332.6 Kb Pdf).

The ONS Births Quality and Methodology Information (257.9 Kb Pdf) Document provides overview notes which pull together important qualitative information on the various dimensions of quality as well as providing a summary of methods used to compile birth statistics.

There is a new version of the interactive mapping tool which enables the total fertility rate to be analysed at the local level for the years 2001 to 2014. The tool now includes revised rates for 2002 to 2010 which have been calculated using population estimates revised to take account of the 2011 Census.

The "Childbearing of UK and non-UK born women living in the UK" reports provide statistics and analysis on births by country of birth of mother. They are available in

Zumpe, J, Dormon, O, and Jefferies, J (2012) Childbearing among UK born and non-UK born women living in the UK. Office for National Statistics.

Dormon, O (2014) Childbearing of UK and non-UK born women living in the UK, 2011 Census data. Office for National Statistics.

International comparisons of live birth rates are available in the Vital Statistics: Population and Health Reference Tables.

Annual summary birth statistics for the UK and its constituent countries can be found in the Vital Statistics: Population and Health Reference tables.

National Records of Scotland provides more detailed birth statistics for Scotland, including cumulative fertility by cohort.

The Northern Ireland Statistics and Research Agency provides more detailed birth statistics for Northern Ireland, including cumulative fertility by cohort.

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11 .Data sources and changes to data

Birth data used in this publication are collected from compulsory birth registrations. Every Registrar of Births and Deaths is required to secure the prompt registration of births occurring within the sub-district covered. Registration of a birth is legally required within 42 days of its occurrence and the registrar will, if necessary, send a requisition to the person whose duty it is to register the birth.

The coverage of the release is of births occurring, and then registered, in England and Wales. Births to residents of England and Wales which are registered elsewhere are thus excluded, while births registered in England and Wales to mothers whose usual residence is elsewhere are included. This means that births to women who subsequently migrate out of England and Wales are included in the numerator for calculations, but the women may not be included in the denominator. The reverse is true for women who give birth abroad then migrate to England and Wales (and do not have a subsequent birth).

The population estimates used for the calculation of fertility rates are the latest consistent estimates available at the time of production. Further information on population estimates and their methodology can be found online.

Estimates of childlessness and number of children are based on estimates of true birth order. Up to May 2012, the number of previous births was only collected, at birth registration, from married women. This partial information on birth order from registration data was supplemented with data from the General Lifestyle Survey.

During May 2012 changes were made to the Population Statistics Act 1938, which means that information on the number of previous children and whether previously married is now collected from all mothers at birth registration and not just from married women. This has a small impact on a number of tables and proposals for changes (66.2 Kb Pdf) to outputs for 2012 and 2013 data were outlined on our website in July 2012. Feedback from users was invited. No feedback was received so the planned changes are being implemented. The cohort fertility figures and tables presented in this report include a full year of the newer, more complete, data.

A paper describing the changes that have occurred to our birth statistics as a result of improvements to the Population Statistics Act (538.8 Kb Pdf) is available on our website. It provides background to the changes and provides high level findings from the new data collected in 2012 and 2013.

This birth order information, both the new complete data, and the older estimated data, is combined over a number of years with population estimates to create a picture of the fertility for each cohort. As more years of data are added, each cohort moves towards completed fertility by adding in births each year to the estimated population exposed to those births (that is, childless women having a birth in 1 year are then part of the population who could have a second birth in the next year). It is only possible to present cohort fertility information for women, as men are not required to give information on previous births at birth registration.

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12 .Background notes

  1. Cohort fertility analysis allows the fertility experience of a group of women sharing the same year of birth (a cohort) to be traced through time and compared with the experience of other cohorts. Statistics relating to the family building of women born in given years shed light on the trends underlying year-to-year changes in fertility and are particularly valuable in helping to formulate models of future fertility.

    Period measures of fertility, such as the Total Fertility Rate (TFR), provide a timely snapshot of the intensity of childbearing in a particular year. However, the TFR should not be interpreted as a measure of family size because it is affected by the timing of childbearing. The TFR is likely to under- or over-estimate average family size during periods where women are delaying having children or later catching up. Cohort fertility analysis may not be as timely, but provides an accurate measure of trends in family size.

    The TFR in England and Wales of 1.83 children per woman in 2014 represents the current level of childbearing among women of all childbearing ages. The average family size of 1.91 children is for women who have completed their childbearing in 2014. The 2 measures should not be directly compared for the reasons noted above.

  2. A woman is assumed to have completed her childbearing by the last day she is aged 45, that is, by her 46th birthday (exact age 46). Completed fertility includes fertility rates up to and including age 45. See background note 4 for a more technical explanation.

  3. The ages of women are presented in "exact years". Therefore, figures should be interpreted as the average number of children a woman has had up to that birthday. So childbearing up to exact age 30 includes cumulative fertility through her lifetime up to the day before her 30th birthday. Any childbearing in the 12 months from her 29th birthday onwards will be included in fertility up to exact age 30. See background note 4 for a more technical explanation.

  4. Completed fertility is the sum of age-specific fertility rates for ages 15 to 45 and therefore relates to fertility up to the 46th birthday. In this bulletin the 1969 cohort, who are aged 45 in 2014, are presented as the latest to complete their fertility up to the 46th birthday. Although women born in 1968 will not reach their 46th birthday until 2014, the age-specific fertility rate at age 45 includes births to women aged from 45 years and 0 days to 45 years and 364 days in 2013 and thus fertility up to (but not including) the 46th birthday.

    In calculating estimates of completed family size for women born in different years, an assumption must be made about the year each woman was born, based on her age when she gives birth. In this case it is assumed that births at age 45 in 2014 are to women born in 1969. This assumption is necessary because information on the mother’s year of birth is not available in historic births datasets so has to be assumed from the age of the mother when she gives birth. However, women giving birth at age 45 during 2014 were actually born between January 1968 and December 1969 – half of these women will have their 45th birthday in 2014 (those born in 1969 who give birth after their 45th birthday,) and half will have their 46th birthday in 2014 (those born in 1968 who give birth before their 46th birthday). However, for simplicity the latest cohort to complete their childbearing is presented as the 1969 cohort, with their completed fertility based on the sum of age-specific fertility rates from age 15 in 1984 to age 45 in 2014.

    Similarly, the bulletin presents fertility up to exact age 30 for the 1984 cohort and other cohorts, as age 30 may be considered the mid-point of childbearing age. However, fertility up to the 31st birthday for the 1984 cohort is available in the published Tables 1 and 2 because cumulative fertility to exact age 31 includes the age-specific fertility rate for age 30 in 2014 (from Table 4).

  5. The methods used to create cohort fertility require use of data collected at birth registration from women on the number of previous children they have had. At present the birth registration system does not collect information on the number of previous children a man has had. Without this information it is not possible to produce estimates of the proportion of men who have not fathered a child.

  6. It is also important to note that a man's reproductive span is not as well defined as a woman's, in terms of the upper age at which a man can father a child and so this means we would need a longer time series to calculate cohort measures. Male period fertility rates can be found in another of our releases - Further Parental Characteristics.

  7. There is a large degree of comparability in birth and death statistics between countries within the UK. However, there are some differences although these are believed to have a negligible impact on the comparability of the statistics. These differences are outlined in Quality and Methodology Information document for births (257.9 Kb Pdf).

  8. Special extracts and tabulations of births data for England and Wales are available to order for a charge (subject to legal frameworks, disclosure control, resources and agreements of costs, where appropriate). Such enquiries should be made to:

    Vital Statistics Outputs Branch (VSOB)
    Tel: +44 (0)1329 444 110
    Email: vsob@ons.gsi.gov.uk

    Enquiries on Childbearing for women born in different years, England and Wales, should be made to:
    Demographic Analysis Unit (DAU)
    Tel: +44 (0)1329 444 644
    E-mail: fertility@ons.gsi.gov.uk

  9. We would welcome feedback on the content, format and relevance of this release. If feedback relates to this Childbearing for women born in different years release, please send to: fertility@ons.gsi.gov.uk. If it relates to Characteristics of mother 2 or Further parental characteristics, please send feedback to: VSOB@ons.gsi.gov.uk.

  10. An overview of Population Statistics is available on our website and a newsletter is updated frequently.

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Contact details for this Statistical bulletin

Oliver Dormon
fertility@ons.gsi.gov.uk
Telephone: +44 (0)1329 44 4644