Everyone knows that our birth rate is now much lower than 20 years ago. It fell sharply from 1980 to 1994, and, although it has since recovered somewhat, the number of babies born last year was 20,000 fewer than in 1980 - a drop of well over one-quarter.
A decline in marital fertility is widely believed to account for this phenomenon. In fact, this is only one factor. Others are changes in the number of women who are of child-bearing age; the age distribution of women within this group; changes in non-marital as well as marital fertility; and, most important of all, I believe, the proportion of women who marry at different ages.
It is worthwhile to try to disentangle these factors with a view to establishing what part they have played in the decline in births in the past two decades. Data for the census years 1981 and 1996 offer the necessary detailed material to establish what happened over a 15-year period.
The first point that emerges from these data is that in 1996 the number of women aged 17 to 45 was almost one-fifth higher than it had been in 1981 - but with almost seven-eighths of this increase concentrated in the upper half of this age group.
If the marriage pattern of 1981 had been maintained, and if fertility, both marital and non-marital, had remained unaltered, this increase in the number of women of child-bearing age would have led to an increase of about 10,000 in the number of births, about 8,000 of which would have been marital births. In fact during this 15-year period the number of births fell by 22,000. And that leaves a difference of 32,000 births to be accounted for.
The conventional explanation for such a huge change in the number of births in relation to the female population of child-bearing age is a drop in the fertility rate, viz. the number of children born to women at each age. And it is certainly true that marital fertility fell during this period.
But lower marital fertility actually accounted for only 10,000 of the 32,000 missing births during this 1981-1996 period, while non-marital fertility increased sharply - to between twice and three times its 1981 level.
The missing factor in all this is the huge change that took place during this period in relation to marriage. The number of married women under the age of 34 fell during this period by 80,000, or almost two-fifths, while the number of unmarried women and widows rose by an even larger amount - by 115,000, or one-half.
This huge shift in the marital status of younger married women since 1981 has had profound effects upon the birth rate. For, although the non-marital birth rate more than doubled during this period, it still remained well below the marital birth rate.
By 1996 the non-marital birth rate averaged around 3.5 per cent for women aged 19 to 34, which meant that about one unmarried women out of 30 had a baby in that year. By contrast, the marital birth rate for this age group ranged from 13 per cent for 34-year-olds up to 40 per cent for 19-year-olds. For those in the middle of this range, i.e. those aged 23 to 30, it was around 20 per cent to 25 per cent, viz a baby was born every fourth or fifth year to married women in that age group.
The fact that in 1996 many more women were unmarried than in 1981 and that unmarried women are very much less likely to have babies provides the explanation for almost 22,000 of the drop of 32,000 in the number of births by comparison with what would have taken place if the same marital and fertility conditions had applied in 1996 as in 1981. To the impact of this factor the decline in marital fertility added a further drop of 10,000, so it accounted for less than one-third of the drop in the marital birth rate.
While the same detailed information is not available in respect of the second half of the 1990s, it is possible to make some evaluation of changes that have taken place in the past few years. What is striking about this period is the fact that since 1995 the earlier decline in the birth rate has been reversed: in 1999 one-tenth more babies were born than in the middle of the decade.
During this three-year period marital fertility actually rose by between 4 per cent and 10 per cent in most age groups - the exception being the 25-29 cohort - but because of a continued sharp decline in the number of married women in their 20s (the age group in respect of which fertility is relatively high), the overall number of marital births nevertheless fell slightly. In terms of births this drop was not fully compensated by the fact that there was an equivalent increase in the number of married women in their 30s - for the fertility of that age group is only half that of the younger group of women in their 20s. With the number of marital births thus slightly reduced between 1996 and 1999, the rise in the overall birth rate between 1996 and 1999 was wholly attributable to an increase of almost one-sixth in the number of single people aged 25 to 39 during this three-year period which was combined with an increase of one-quarter in the non-marital fertility rate for that age group. Because of that combination of factors, within this brief period the total number of births to unmarried women in this age group jumped by almost half.
What is particularly striking is the way in which for older women of child-bearing age the non-marital fertility rate is now approaching that for married women. By contrast, in the case of women in their 20s the fertility rate for married women is still five times greater than that for single women.
These developments raise many questions. Will the 1996-1999 recovery in fertility in most age groups continue, or at least be maintained? Is the rise in the marriage rate since the mid-1990s eventually going to have some impact on the marital birth rate, or is this development going to be outweighed by other factors? How far is the substitution of non-marital for marital births going to go? And is the equality of fertility between married and single women in their early 40s going to spread downwards to younger age groups?
Above all, what long-term impact are these dramatic demographic changes going to have on our society in the decades ahead? To what extent can non-marital unions achieve the same measure of stability as marital unions? And how far will the traditional stability of marital unions be undermined by marriage breakdown? Already one in every 10 married women in Dublin is separated from her husband.
Both in their magnitude and in the speed at which they have been happening, the demographic changes that have been taking place during the past two decades are dramatic. Yet they evoke little public comment and have so far had no impact whatever upon the political scene. Is this political neglect of these fundamental changes in our society going to persist indefinitely, or can we expect our political leadership at some point to start to recognise and address them?
gfitzgerald@irish-times.ie