Last week, I found myself at a glamorous smarty party — the kind where you are expected to look sharp and act sharp — and guess what the number one topic of conversation was. Which is the better film: Up or Fantastic Mr Fox? The Pixar cartoon about an old man, a boy scout and a floating house, or the animated Roald Dahl story? And we’re not talking about mothers of small children comparing notes. We’re talking both sexes (some childless) earnestly debating the two films’ relative merits, just as you might discuss Oscar nominations or Cheryl Cole v Dannii Minogue. Quite weird, no? Then again, the Up v FMF debate is so 2009, you couldn’t make it up.

There is nothing new about adults muscling in on the younger generation’s territory and claiming it as their own. It’s been more than a decade since you spotted men in suits on the Tube reading Harry Potter, and even longer since mums stopped dressing like mums and regressed to dressing like their teenage daughters. But now we’re taking the trend to its logical conclusion and making kiddie stuff — the icons of the playgroup and the playground — part of our adult world.

You name the kiddie habit, and the grown-ups are onto it. Playing with iPhone applications, particularly Pacman. Sharing music, and not just the remastered Beatles, as you might expect, but 19-year-old Taylor Swift’s Love Story (the equivalent of Donny’s Puppy Love). George Clooney may be the chocolatey voice of the Fantastic Mr Fox, but women are swooning over Robert Pattinson, because he stars as a 17-year-old vampire in the Twilight movies, which makes him more fun to have a crush on. Even fashion has taken a kiddie pill: the surprise must-have for winter is those Louis Vuitton rabbit ears, and, for next season, Giles Deacon has grasped the nettle and gone straight back to the toy department with bags in the shape of fluffy dinosaurs. It started with women wearing friendship bracelets, then getting into Facebook, Gossip Girl and name necklaces; now there is nothing too junior or lowbrow or High School Musical for us not to welcome it into our lives.

The explanation for this universal midlife crisis has been, to date, that we don’t want to miss out, or grow up. But the latest development — the Up v FMF question — suggests there is more going on. Could it be nostalgia, a collective hankering for a lost innocence? When you’re in the cinema watching Twilight, you know you’re safe and that there will be a wholesome message about love, loyalty and redemption. The same goes for Up and FMF (with its shades of The Wombles).

Meanwhile, with real life so X-rated and “some viewers might find disturbing”, and every adult — apart from David Attenborough — on the make, junior culture has become our flower movement. If you can huddle in a corner at a party and tell each other where exactly you cried in Up, it’s like saying, “We want the world to be a nice place with values, don’t we? We’re not all shits.” Either that, or we’re a bunch of shallow babies. It’s hard to say for sure.

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