I began wondering about this the other night while reading a book with my daughter. She’s at that pre-speech pointing age where I name something and she points to it. This works very well until we get to a picture of a family and I ask: where’s the nanna? She immediately points to the mother.

Thinking she’s made a mistake, I ask her again. Where’s the nanna? “Nanna” she insists, pointing to the mother. No, THIS is the nanna, I encourage, pointing at the actual nanna. “NANNA” she repeats patiently, pointing to the mother as if I am, in fact, an idiot and also possibly blind. If my daughter possessed the requisite fine motor skills to roll her eyes right now, she would.

In the middle of our standoff, I suddenly realise the problem. The book’s illustration of a plump grandmother with spectacles, apron and grey hair is ridiculously outdated. Nannas have moved on.  Nannas have re-invented themselves. Grey hair? You must be kidding. Bifocals? Pah! Nanna had eye laser surgery. Plump?  Don’t be silly, Nanna does yoga. Aprons and shawls? Oh please. Nanna wears jeans.  And knitting? Are you on crack?

No wonder my daughter was so perplexed when I kept insisting that the grey haired frump in her book was a nanna. She doesn’t know anyone who looks like that. Certainly not her own nannas who both, it must be said, do resemble the mother in that picture far more than the grandmother.

You know, I don’t think my daughter has ever even seen a real, live woman with grey hair. Certainly not in her extended family. Even her two great-grandmothers aren’t grey.

Excuse me, but where did all the little old ladies go? Straight in the bin marked “Old Fashioned Stereotype” is where. Baby boomers are – SURPRISE! – re-inventing what grandparenting looks like, the same way they’ve re-invented every other life stage they’ve passed through. And if I may say so, they’re doing a sterling job of it.

Women in their 50s, 60s and even 70s today are almost unrecognisable from women the same age in previous generations. I’m not talking about surgery freaks or 60 year olds obsessed with trying to look 30. They’re scary. I’m talking about regular nannas who simply don’t see the need to look or act like Mrs Doubtfire while they empty their nests and march confidently into retirement.

When I was a kid, grandparents had grey hair. They just did. All of them. It was non-negotiable. And they did not wear denim under any circumstances. AS IF.  My grandmother knitted and baked and was grandmotherly in every way. Just like nanna pictures in books.

Shockingly, I called her Grandma. You don’t hear that word much these days (let alone Granny) because most Hot Nannas have banned it. “Frankly, it sounds so….OLD”, they shudder collectively.  And boomers don’t really do old.  Never have. Not starting now thanks. My kids have a Nanna and a Nonna. But even those terms are too elderly for some boomer grandmothers. A quick poll entitled “What-do-your-kids-call-their-grandmother?” revealed a flock of funky 60-somethings known to their grandkids as “Queenie”, “Patty”, “Mimi”, “Narnee”, “Ju-Ju”, “Gigi”, “Jeanie”, “Chrissy”, “Robbie” and “Zazee”.

And the granddads? Not so much. Pa, Pop or Grandpa seem to be the extent of it. Boomer blokes don’t seem to care what they’re called or what colour their hair is. “We’ve got no fight left in us after all those years spent living with the hot gals!” notes my Dad with a happy shrug. He is a “Pa” and cool with it.

So let’s do a quick recap: the modern nanna has given the grandmother moniker and appearance a kick-ass makeover. But what about the grandmotherly lifestyle?  Not much cake baking or knitting going on. Leave that for the Gen Y girls to do with irony. Hot Nanna is more likely to be found at a bungy jump than a bingo hall. One friend’s two-year-old son points skywards whenever a plane flies past and shouts “Hi Nanna!” because she is so often interstate on business or overseas on holidays.  Grey Nomads, hello.

One night last year, my son called his nanna on her mobile. “Hi darling!” she exclaimed, delighted as always to hear from him. “Can I call you back in an hour? Pa and I are just in Tanzania dancing with the Massai Warriors.” He was not at all phased by this. To him, this is the kind of thing that grandparents do. For the current generation of kids, grandparents are fun and cool.  Far more fun and cool than Mum and Dad who are boring and embarrassing. (An aside: The fact that our kids and parents are so keen to hang out together is terrific news for those of us who rely on their help with childcare. A recent study estimated Australian grandparents contribute around $75m worth of free childcare per year. You’ve got to be grateful for that.) Of course, at the top of the Hot Nanna tree are the celebrity nannas. Those boomer icons like Jane Fonda, Diane Von Furstenburg, Twiggy, Sally Field, Priscilla Presley and Barbara Streisand. My favourite, though, is Goldie Hawn who is known to her grandson as “Glam-ma”. And so say all of us.