Interpreting Australia's fertility increase.

Author:Heard, Genevieve

After decades of decline, Australia's fertility rate has been rising. How should this phenomenon he interpreted? This paper assesses the nature of the increase and reviews some of the explanations put forward for the reversal in the direction of fertility change.


Discussion of Australia's recent 'baby boom' often relates to birth numbers, which have risen steadily since 2001 and reached a record 296,600 in 2008. (1) While birth numbers arc partly a function of the number of reproductive-aged women in the population, population growth cannot account for this increase. Rather, the number of babies per woman, as measured by the total fertility rate (TFR), has also increased.

The TFR was 1.97 in 2008, substantially higher than the low of 1.73 babies per woman recorded in 2001. (2) This increase follows consistent decline in the TFR since the peak of the post-war baby boom, and coincides with similar increases in other western countries. (3) The change in direction has attracted much interest, following as it does a period of heightened concern over low fertility as a primary cause of population ageing around the developed world.

Of particular interest is whether higher TFRs can be sustained or will prove to be but a temporary aberration in demographic history. While it is impossible to predict the future, the answer to this question surely lies in the reasons for the increase. This paper assesses some of the explanations put forward for the reversal in the Australian context.


The total fertility rate measures fertility over a finite period of time (often, and for the purposes of this article, a calendar year). The TFR is the sum of age-specific fertility rates (ASFRs), and as such represents the number of babies each woman would have if she were to experience all the ASFRs of that year. In essence, a single year's data is used to estimate childbearing per woman, which in reality takes place over many years.

Measures of period fertility such as the TFR are important to the debate over population ageing, because fertility in any given year affects the age structure of the population. However, such measures are known to be subject to considerable distortions caused by changes in the timing of childbearing among cohorts of women. (4)

The average age of mothers increased dramatically in most developed countries in the latter half of the twentieth century, engendering discussion about the phenomenon of delayed childbearing. (5) In Australia, the median age of mothers rose steadily from 25.4 years in 1971 (the lowest on record) to 30.8 years in 2006. (6) During a shift to older ages at childbearing, fertility declines among younger women before any increase in fertility becomes evident among older women. Therefore, delayed childbearing temporarily depresses the TFR, whether or not it has any impact on completed fertility (ultimate family size). The negative effect of this shift on period fertility rates around the developed world is widely acknowledged. (7)

Conversely, if and when women who postponed childbearing do have children at higher ages, they will provide a boost to the fertility rates of those age groups, and to the TFR. The increase in Australia's TFR since 2001 is largely attributable to births to women aged 30 to 39 years. (8) Though the trend towards births at higher ages has been evident for decades, the fertility rates of women aged in their thirties have accelerated since the turn of the century (Figure 1). This is consistent with the recuperation hypothesis; that is, women in their thirties are now making up for births delayed while they were in their twenties.


In addition to the continuing increase in the fertility rates of older women, the long-term decline in the fertility rates of younger women appears to have been halted (Figure 1), lending weight to declarations that the postponement of childbearing has come to an end. (9) Since there is a biological limit to how long women can delay childbearing, it was to be expected that the increase in the average ages of mothers would eventually slow or cease. In addition, there has been considerable publicity surrounding women 'leaving it too late' and being unable to have the number of children they desire--more so in Australia than elsewhere, according to McDonald. (10) However, it is difficult to verify McDonald's claim that increased awareness of age-related fecundity problems has affected the timing of births.

The developments described so far are consistent with projections of the Australian TFR published by Kippen in this journal in 2004. (11) Under one scenario, Kippen assumed that 'the postponement of fertility halts; that is, fertility stops declining at younger ages but continues increasing at older ages ...', resulting in a steady increase in the TFR. Although considered an 'unlikely option' at the time, this scenario has now come to pass. Indeed, Australia's TFR has increased much faster and to a level considerably higher (1.97 in 2008) than projected even under this scenario (1.85 by 2015). (12)

The difference is due to the fact that fertility among younger women has not only stabilised but increased (Figure 1). Following several decades of steep decline since 1980, the fertility rate of women aged 20 to 24 years increased from 51.4 to 57.1 babies per 1,000 women between 2006 and 2008. Similarly, the fertility rate of women aged 25 to 29 years increased from 101.0 to 105.8 babies per 1,000 women. Even teenage motherhood has increased, from 15.3 to 17.3 babies per 1,000 women over the same two-year period. (13)

In their analysis of Recent Trends in Australian Fertility for the Productivity Commission, Lattimore and Pobke contend that the increased age-specific fertility rates (ASFRs) of younger women signal a quantum rise in fertility, over and above tempo effects including the cessation of postponement. Data from the large-scale longitudinal Household Income and Labour Dynamics in Australia (HILDA) Survey is adduced in support of this argument. The period of increased fertility in Australia has coincided with an increase of around 0.15 babies in the expected lifetime fertility of younger women, with fewer anticipating childlessness, and with more positive responses to questions about the desirability and likelihood of future children. (14)

In reality, as Lattimore and Pobke concede, quantum effects are to some degree inseparable from tempo effects, because 'conditions that are conducive to earlier childbearing are also likely to prompt increased fertility'. (15) This brings us to discussion of the wider social and...

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