Trying to keep my four-year-old under control during a christening service recently I was glad when he picked up the order of service and began to study it hard. Then he pretended to start reading it.
He whispered: "And this is the story of when Jesus...met Batman."
It made my wife and I chuckle and showed a good deal of creative thinking, but it also revealed just how pre-occupied with superheroes he is. The funny thing is that he has never owned a Batman toy or worn a Spider Man outfit. He hasn't even seen Ben 10 on the telly.
Yet for months he has been coming back from pre-school wanting to pretend to be Superman, the Incredible Hulk or one of the other iconic characters. Each game involves basically catching baddies and a certain amount of implied violence.
Don't get me wrong, I've got nothing against superheroes per se. In fact, in my time I've enjoyed a Batman movie or two. But I have discovered from other parents that I am not alone in worrying that at such a young age he is not yet ready for this stuff. I would rather he was still obsessed with Thomas the Tank Engine or Postman Pat than the Green Lantern or Power Rangers.
The main reason for my concern has been that superhero play tends to involve too many themes of death and destruction. And what I find startling is the idea that it is so powerful that my son has latched on to it through simply playing with other children. I fear how obsessed he could become if he actually started watching superhero shows on the television.
I'm also alarmed at the way in which superheroes are all pervasive for youngsters. They take over everywhere from themed birthday parties to lunchboxes. Visit any supermarket and it's clear that there is a sustained commercial drive to hook them into the superhero world as early as possible.
My son is certainly not alone. Many of his friends – the male ones at least – are equally obsessed.
The question is why are they so addictive? And does it matter?
Research certainly bears out the fact that this age group are naturally drawn to the subject and a survey of teachers in America found that half often intervened to re-direct superhero style play.
Yet two US academics, Mary Ellin Logue and Hattie Harvey, found that "bad guy" play like this could actually improve children's conversation and imaginative writing as well as teaching them important things about morality and self-restraint.
Many child psychologists believe that the reason superhero play is so attractive to four and five-year-olds is that it's an age when they are trying to find their place in the world and assert themselves. Imagining that they are superheroes allows them to pretend to have a level of power and independence that they do not have in a world ruled by teachers and parents.
One study from the Cornell University Food and Brand Lab found that children can be encouraged to order healthier food through thinking about what their favourite superhero would eat.
This got me thinking about my own childhood. When I was a kid we were obsessed with toy soldiers or Cowboys and Indians, subjects all of which involved guns, fighting and death. It doesn't appear to have turned me into a psychopath, despite being arguably more morally corrupting than superheroes where the message, by and large, is about doing good. So perhaps, there's no reason to think my son's superhero phase will make him any more aggressive.
Then, the other week there was a moment when I became more relaxed about the whole thing. Once again, while in the garden, my son had asked me if I wanted to play superheroes with him. OK, I said, somewhat wearily. "Right," he said, "I'll be Batman and you can be Iron Man."
"So what does Iron Man do then?" I said. It was clear he hadn't a clue.
He thought for a moment and said: "Er, he does the ironing!"
The next time he wants to run round the house turning a towel into a cape, I'm going to be more relaxed about it.
But he's still not watching Teenage Mutant Ninja Turtles until we're good and ready.