Ever had a moment when someone has deeply insulted you but you only come up with the perfect retort later? You kick yourself, wishing you had been faster, feistier and less tongue-tied. The French have an expression for this: L'esprit de l'escalier - staircase wit - or the frustrating experience of thinking of a clever comeback too late, when one has already left and is half-way down the stairs.

I had one of those moments recently with the Prime Minister. I was at a function where Kevin Rudd was giving the keynote address. He talked about the ''crisis'' of Australia's ageing population and the various economic challenges we will face as a result.

Studies show that children benefit from having one or more tertiary-educated parents. Credit:Andrew Taylor

Arguments were made about superannuation and the strain on healthcare. But there was a deeper message: young people (women in particular) are failing in their civic duty to reproduce. Apparently, gen Y is to blame for the inverted population pyramid.

There were hundreds of people in the room but only a handful under 30. As one of the under 30-crowd, I shuffled nervously, hoping no one would recognise me - and my empty womb - as the deeply unpatriotic and traitorous felons that we are.