Have you ever noticed how the Treasurer, Peter Costello, tries to suppress a little smirk when he has sex on his mind? To be fair, it may not be the lacy, bodice-ripping, kind of lust he’s thinking about. It’s perhaps something a little more prosaic. Nevertheless, it seems to make him happy.

He was smiling back on budget day in 2004 when he told journalists to ”go home and do your patriotic duty tonight”. He urged us all to ”have one for your husband and one for your wife and one for the country”. In a lacklustre election year, the little hint at smut was a godsend. What was then dubbed the ”erection budget” quickly became a headline writer’s wet-dream: ”F-word used in erection year”, teased one headline; ”Go forth and multiply”; ”Lie back and think of your country”. Even Prime Minister John Howard got into the spirit of things with a breathy ”Come on, come on, your nation needs you!”

As an incentive to get us all in the mood for love, sex and the breeding creed, Costello introduced a $3000 baby bonus and increased family benefits.

Now leaping forward more than two years and it seems Australian women have been doing their bit.

Thursday’s release of the latest population data and preliminary birth figures by the Australian Bureau of Statistics show a healthy birth rate on the rise.

”Number of births soars” was the screamer headline on Costello’s media release. And it’s a good bet Costello’s sexy smirk broke into a broad-faced smile as he congratulated himself , yet again, for being the proud father of a ”baby boom’.

But Costello might be well advised to take a cold shower.

There are a number of reasons why Australia’s birth-rate has improved and is looking healthy at the moment. And Costello might be claiming a little more credit than he deserves.

To suggest that government policies, such as the $3000-$5000 baby bonus is responsible for women deciding to have a baby is simplistic, at best. But such a claim is of course impossible to test, unless each of the mothers of the 265,031 babies born last year is interviewed about her motivations for having a child. Certainly a baby bonus is helpful and indeed welcome, particularly given the absence of maternity payments in Australia. But it is unlikely to be the decider. If it is, then the woman shouldn’t be having a baby at all.

It’s a bit rich to hear the Federal Government boast about the effect policy has on Australian fertility, when for decades there was a bipartisan acceptance that governments should stay out of the bedroom. The over-riding assumption was that policy couldn’t and wouldn’t influence the very personal and intimate decisions people make about their lives and choice to have a family. In fact so strong was the notion of keeping the peoples’ procreation private, successive governments refused to hear the insistent warnings from leading demographers to be alert to our declining fertility rate, which until recently had been in free fall for four decades.

Right now Costello may enjoy basking in the glow of this week’s headline suggesting he’s the ”father of a reborn urge to multiply”. However, a little modesty might be called for here. The Department of Treasury initially took some convincing that a baby bonus was a good idea. The real drive for such a policy came from several right-wing backbenchers who had the ear of Howard.

The baby bonus, however, is just one of a number of measures the Federal Government now points to as reason for the rise in births. Increased family benefits, extra child-care places and the child-care rebate are also often cited as policy initiatives responsible for turning the ”baby bust” around to a ”baby boom”. Again – while none of this can be proven – it’s fair to say that the strong ”perception” created by such initiatives has encouraged a sense of Australia being much more family-friendly than it perhaps is. Plenty of government lip service has been paid to encourage the notion that breeding is good for the nation, and that motherhood is virtuous. And women are traditionally suckers for being both ”good” and ”virtuous”.

However, there are two strong and powerful forces behind the current boom in births that Australia is witnessing, and neither has anything to do with current policy. One of those reasons is historical, the other is social.

The historical one is simple. Girls born during the peak of the postwar baby boom hit the median age of first-time mothers (25 years) in about 1971. In that year Australia produced its biggest crop of babies ever, a whopping 276,361 little Aussies were born. That year was then dubbed the ”first echo” of the baby boom. The second echo was expected in about 2001-2002, when the girls from that big ’71 crop reached about 30 years old – the new median age of first- time mothers. But, true to form around the Western world, those Generation X girls delayed starting their families for a few years, or more. It’s only now that those girls – by now in their mid-30s – are beginning to breed. This current spike in births is the ”second echo” of the baby boom. It was long expected, but just a little late. Demographers knew it was coming. And so too did the Government.

The second factor behind the current baby boom – or blip – is to do with a powerful social force. This is by far the most significant factor behind the current breeding trend, and it has nothing to do with demography, data or government policies. It is simply this – women talk. They talk to one another, about one another, for one another. We share our stories and learn from our shared mistakes.

When the issue of age-related infertility and childlessness awkwardly raised its head in the Australian media back in 2002, it was as if a dam wall had suddenly collapsed and the floodgates burst open. Suddenly women everywhere had something to say about their experience of motherhood, delayed childbearing and the pain of childlessness. The full pelt of that very public and at times very controversial discussion has touched all Australians. But most of all it has reached the ears and minds of young women who are now considering their options and contemplating their futures with a strategic drive that is nothing short of awe- inspiring. Costello, you can not take the credit for that.