Those diamond-shaped yellow-and-black 'Baby on Board!' signs have been adorning the back windows of station wagons and family cars since the 1980s.
Reactions to these signs continue to be polarised. Some people wouldn't be seen dead with one on their vehicle while others rush to The Warehouse and snap them up for $5.29 a piece.
The full significance of the message is a matter of debate. The Warehouse's website says they're for "[p]rotecting our most precious cargo". But, how exactly are they protecting anyone?
Some people claim they do quite the reverse - that advertising you have a baby on board is an invitation to kidnappers and human traffickers. Meanwhile myth-busting website snopes.com refutes claims these signs were invented in response to the death of an infant who was overlooked by emergency response crews following a car accident.
I've never understood the core purpose of such signs.
Are they to boast about your fecundity? Encourage road-users to drive more safely? Enable legitimate use of car-pool lanes? Or are they just a cute gimmick with no special meaning at all?
In any case, they spawned some amusing spin-off signs such as "Mother-in-law in boot".
It's generally agreed that the intended message is: "There's a baby in the car so drive carefully." But it's a weird message, implying as it does that we're likely to drive recklessly in the absence of these signs.
Cartoon character Marge Simpson put it well when she acquired a 'Baby on Board!' sticker.
"Now people will stop intentionally ramming our car," she quipped.
Thanks to stickers depicting line-drawing figures, these days there's a whole new way to wear your family on your vehicle's rear windscreen.
One Monday morning in August I stopped at traffic lights somewhere near Albany. The red Toyota RAV4 in front of me showed a mum, dad, three children, a cat - and one angel baby, complete with halo, hovering above the rest of the family.
It instantly humanised the occupants of the car. I certainly wouldn't be showing impatience or cursing at any slowness to take off from the lights now that I was aware of the driver's personal circumstances. I couldn't stop thinking about the tragedy of their wee angel baby as I followed them along the road.
If those seven little stickers on the back of that car so easily personalised the driver for me maybe they should be made compulsory in order to reduce the incidence of road-rage.
It's one thing to feel animosity towards a faceless, anonymous driver of a vehicle moving erratically but pretty difficult to have the same reaction towards someone for whom we've acquired empathy.
But just like the 'Baby on Board!' signs, these stickers elicit mixed reactions. Are they twee and tacky or just a bit of fun?
At thestickerfamily.com.au you can choose from 136 different characters including shopping mums, bald dads, girl gymnasts, nose-picking boys, grandmothers in wheelchairs, bearded grandfathers and a variety of family pets.
Some enthusiasts say that such personalised windscreens help their children recognise the family vehicle in crowded car-parks. That may be so but I believe the vast majority of people who purchase these stickers do so because they just look so darn cute.
Of course, if cuteness really doesn't appeal see theotherstickerfamily.com for an irreverent range of characters including couch potato, junkie, coke head and flasher.