Do you remember 'The Snapper'? Roddy Doyle's classic second book of the Barrytown Trilogy, published in 1990, revolves around the Rabbitte family and the teenage pregnancy of Sharon Rabbitte.
Written in the late 1980s, it is a familiar tale about a family dealing with a teenage pregnancy and how the birth of the Snapper itself brings the family closer.
When I was a teenager, teen pregnancies were the stuff of growing up, like drinking in fields, 12-inch singles and smoking your first Major.
In 1990, 6pc of all mothers in Ireland were under 20. On our road in suburban Dublin, when an unmarried girl became pregnant, it was treated as if the sky had fallen in. News always travelled fast. Initially, particularly amongst the sanctimonious, there'd be all sorts of gossip and chatter about the girl as if a girl could get pregnant on her own. A mate of mine's mother used to warn us boys as we headed out the door on a Saturday night, "Remember now lads, they can't get half-pregnant"!
Back then, I didn't really know what she meant. I was a bit slow. Now I get it. The truth is that all data show that teenage pregnancies are hard on the mother, the family and the baby. Over the years, teenage pregnancy has been an accurate indicator of relative poverty because obviously it is very difficult for a young mother to build a career or stay in education if she has a baby to look after.
And the evidence from the US (where they have the most relevant data) shows that your mid-twenties are very important in terms of building a solid career foundation. For example, people who are not working for long periods in their twenties never recover financially. They still earn less than the average by the time they are 40 and 50. So these years are crucial economically and, if you are looking after a young baby or child in these critical years, it is hard to catch up financially.
The good news is that teenage pregnancy has fallen in Ireland to the lowest level on record and is still falling every year.
This year, fewer than 2pc of babies will be born to mothers under 20. Teenage pregnancy in Ireland is disappearing fast, despite the fact that the age at which Irish teenagers lose their virginity is also falling rapidly. A recent Unicef report found that Irish girls are more likely than boys to have lost their virginity by their mid-teens; 22pc of Irish girls had sex at the age of 15 or younger, with the figure for boys at 19pc. Four out of 10 respondents to the Unicef survey lost their virginity after drinking alcohol - no surprise there.
Yet in the past decade, from 2003 to 2013, there has been a staggering 51pc fall in the numbers of babies born to women under 20. This is a phenomenal change in behaviour.
Obviously use of contraception is the major reason for the fall in pregnancy. It is hard to believe that contraception was illegal in this country not so long ago.
However, the falling trend in teenage pregnancy is not unique to Ireland; we are seeing similar patterns in the UK and the US. In the US, some economists have argued that popular TV programmes such as MTV's hugely successful '16 and Pregnant' - which was initially criticised for glamorizing teenage pregnancy - has actually had the opposite effect. The show started in 2009 and since then there has been a 10pc fall in the number of teenage girls in the US having children. Researchers wanted to know why. By mapping the online reaction to the show via Twitter, Facebook and online Google searches, they saw a spike in searches for words like "contraception" and "abortion" coincident with the show. Meanwhile on Twitter, hashtags such as "don't forget your pill" or "remember birth control" accompanied comments on the show.
When presented with the reality of teenage motherhood, including arguments with the boyfriend, not having enough money or not being able to go out partying with the mates, many teenagers have reacted with caution rather than abandon.
Whatever the reasons - be they social, scientific or anecdotal - teenage pregnancy is disappearing fast. Meanwhile, the number of older women having babies is increasing rapidly. In Ireland in the past 10 years, the number of women over 40 having babies has increased by a staggering 78pc.
In 2003, 2,250 mothers were over 40; by 2013, that figure had risen to 4,004 and it is rising progressively every year.
So we now have the oldest Irish mothers on record. Look at the chart. It shows the trend in the average age of the Irish mother since 1955. Having fallen rapidly until the 1980s, Irish mothers have been getting older. Even the average age of the first-time mother has increased from 28 to 30 in the past 10 years. These differences may seem small, but they are revolutionary because they reveal a significant change in the place of women in Irish society and in the Irish economy over the past 10 years. Nothing more underscores the freedom of women than the freedom to choose when they want to have children. We see this all over the world. The single best indicator of the equality of the sexes and economic development in societies is family size. Poor countries have big families and vice versa, and poor countries are also those societies where women are least equal.
In Ireland, girls are now outperforming boys in all academic league tables. From the Leaving Cert results to university degrees, women are doing better than men. Certain professions that used to be the preserve of the successful man, such as the law and the medical profession, are being gradually feminised. This is resulting in Irish women having fewer babies but having them later in life. Their daughters, seeing this trend and maybe, even subconsciously, taking it on board, are not getting pregnant when they are teenagers despite having more sex, younger than their mothers.
These are profound changes; they are permanent and are rooted in changed expectations and aspirations on the part of Irish women. They have deep ramifications for education, child-care, housing and taxation policies in the country. At this time of the year, when we speak of nativity plays and their meanings, the one with the most resonance - economically at least - is the nativity drama playing out in every Irish family before our very eyes.