Development of births

The development of births is frequently shown by means of the average number of children per woman. For correct interpretation of that seemingly easy indicator, however, it is important to know whether it refers to a calendar year or to a female cohort. This article explains both measures.

What is the total fertility rate of the calendar years?

The total fertility rate calculated on the basis of the statistics of births for 2010 was an average 1.39 children per woman. The total fertility rate, which is based on one calendar year, is one of the indicators used most frequently in political and public debate. It provides timely and important information on changes in fertility, which usually occur as a result of social, economic or political changes (chart "Total fertility rate of the calendar years"). The total fertility rate of the calendar years, which is independent of the age structure of the population, provides the basis for comparisons of the level of births between various periods or regions. In doing so, differences in fertility according to the woman’s age must also be taken into account.


The total fertility rate of a calendar year refers to all women who were aged between 15 and 49 years in the year examined. When calculating the total fertility rate, it is assumed that those women form a hypothetical cohort. Therefore, the total fertility rate of 2010 is interpreted as follows: if the fertility behaviour of the women in the 35 years between their 15th and their 50th birthday were the same as the average child bearing behaviour of all women aged 15 to 49 years in 2010, they would give birth to about 1.39 children on average in the course of their life. The fertility behaviour is measured using the age-specific birth rates of the women in each age separately from 15 to 49 years. (The age-specific birth rate shows the ratio between the number of children born by mothers of a specific age and the number of all women of that age).

Due to its hypothetical nature, the total fertility rate of the calendar years is suitable only to a limited extent for properly assessing the development of the final number of children born by a woman in the course of her life. For that purpose, the total fertility rate of the female cohorts is used.

Total fertility rate between 1950 and 2010

t the beginning of the 1960s, the two parts of Germany had seen an increase in births, represented by the highest total fertility rates of the post-war period at 2.5 children per woman. The children born in that period are today’s large cohorts of the mid-forties. The subsequent sharp fall in the number of births started as early as in 1964 in the former GDR, and since 1967 the number of births in the former territory of the Federal Republic decreased continuously, too. Consequently, the total fertility rate also decreased strongly.


The decline in the former territory of the Federal Republic lasted for nearly twenty years and in the mid-1980s the total fertility rate reached its all-time low with fewer than 1.3 children per woman. The decrease in the total fertility rate was caused not only by the fact that fewer children were actually born than in the previous years. The decline in fertility was also due to the fact that an ever larger share of the women postponed their starting a family to an older age. Then the total fertility rate rose to 1.45 in 1990 before it fluctuated slightly around 1.4 children per women (except for a few years).
The former GDR counteracted the declining birth rate from the mid-1970s by comprehensive government support for families with children. That policy actually resulted in a short-term increase in the total fertility rate to 1.94 children per woman in 1980. Then fertility gradually decreased here, too. As a consequence of the radical economic and social changes occurring in the new Länder in the context of German unification, the number of births and the total fertility rate fell sharply here: from 1990 to 1994 the total fertility rate was down from 1.52 to 0.77. Since 1995 the fertility thus measured has been growing. In 2007, the women in the new Länder gave birth to an average of 1.37 children, which was the same level as in western Germany. From 2008 onwards, their birth rate was as high as 1.40 children per woman and already exceeded that of the former territory of the Federal Republic.
The results of the continuous birth statistics for calendar year 2010 show a slight increase in the total fertility rate in Germany from 1.36 to 1.39 children per woman. The increase in births from 2009 to 2010 was greater for second and third children than for births of first children.
In the year 2010, the total fertility rate was caused mainly by the women aged 33 to 40 years; they gave birth to more children compared to the women at the same age in previous years.  At the younger ages, the fertility has continued to decline.  

What is the total fertility rate of the female cohorts?

The total fertility rate of the female cohorts corresponds to the average final number of children a woman gives birth to in the course of her life. This rate usually differs from the current total fertility rate, which is based on one calendar year. The total fertility rate of the calendar years refers to a constructed hypothetical cohort. In contrast, the final number of children indicates the specific behaviour pattern regarding family formation of real female cohorts. Most of the women of the older cohorts gave birth to their children at an earlier point in their life than the women of younger generations. During the transition to the new fertility behaviour, which was first shown by the decrease in the fertility of the under 30 year olds, the total fertility rate of the calendar years fell sharply (chart "Total fertility rate of the calendar years"): this happened in the late 1960s to early 1970s in the former territory of the Federal Republic and in the early 1990s in the new Länder. As, however, the late point in time of starting a family does not necessarily mean fewer children, many women “caught up” by giving birth to children at an older age. The increasing age of women when giving birth for the first time actually led to a decreasing final number of children for the women of the cohorts concerned, especially in the former territory of the Federal Republic. However, that decrease was not as serious as was at first expected because of the decrease in the total fertility rate of the calendar years from the late 1960s to the early 1970s.

The number of children born by a female cohort can be calculated through the total fertility rates of the female cohorts. For that purpose, the age-specific birth rates for any age between 15 and 49 years are added up. However, not only a specific calendar year is examined here but, for a female cohort, the age-specific birth rates of the 35 calendar years are taken in which the women of that cohort live the years between their 15th and 50th birthdays. Therefore, the total fertility rates of the female cohorts (also referred to as final number of children) cannot be calculated until the women of the relevant cohort have reached their 50th year, that is, when they have become 49 years old. In 2010 that was the cohort of 1961; the women of that cohort gave birth to an average 1.6 children.

What can be used as an alternative for younger women is the average numbers of children reached until the relevant age (calculated as the sum of the age-specific birth rates until that age). However, the number of children those women will give birth to later is unknown for the time being.

Total fertility rate of the female cohorts from 1930

etween the female cohorts in the former territory of the Federal Republic on the one hand and in the new Länder on the other, there are differences both in the current level and in the previous development of fertility (chart "Total fertility rate of the female cohorts"). In both parts of Germany, the women born in the 1930s gave birth to about the same number of children on average: the total fertility rate of the women of those cohorts was over 2 children per woman. Within the following thirty years, the final number of children per woman was down by about 25% in the former territory of the Federal Republic. The decrease was particularly sharp for the cohorts of 1934 (2.2) and 1943 (1.8). That decline reflected the transition from the highly family-oriented fertility behaviour in the baby boom period (late 1950s to mid-1960s) to new lifestyles and living arrangements, which emerged as a result of the social change in the late 1960s and early 1970s. Afterwards, the decrease continued at a slower pace. The women of the 1961 cohort, who reached the age of 50 in 2010, gave birth to an average 1.6 children in the former territory of the Federal Republic.

lthough in the former GDR the final number of children of the female cohorts decreased, too, that development was smoother after it had started in a similar way as in the former territory of the Federal Republic. Between the cohorts of 1934 and 1947, the final number of children decreased from 2.1 to 1.8 children per woman and remained at this relatively high level for more than a decade. As is shown in the (chart "Total fertility rate of the calendar years")", the annual total fertility rate also decreased considerably in the former GDR in the early 1970s. However, the decline in births did not last long there: from as early as 1976, the total fertility rate of the calendar years increased again. The final number of children of the female cohorts was not affected by that brief decrease.

The 1960 cohort marked a new trend in the cohort fertility of women in eastern Germany. The final number of children born to the 1960 and 1961 cohorts declined as compared to the 1950s cohorts. For the cohorts after 1960, a decreasing final number of children is expected for both parts of Germany. This is at least what is indicated by the level of births of the women who have reached the age of 35. From the 1961 cohort to the 1976 cohort, the average number of children of the 34 year olds was down by 12 % in the former territory of the Federal Republic and by 27 % in the new Länder. Although the number of births is currently rising for women above the age of 35, it will hardly be possible to make up for that deficit by the age of 49 years.

E-mail: demografie@destatis.de