Not that I believe violent movies, or indeed violent computer games and the like, are the sole cause of such actions, but what's happened in the past week has made me think about it a little more. That and the end of the school holidays when every day I seemed to be checking on what games were being played on the computer, or deflecting Nerf bullets, or having to reprimand him about inappropriate conversations about killing people.

OK, it probably wasn't as bad as it sounds. There was also plenty of other things happening, like cuddles and cooking and dancing and reading and playing with the dog in a very relaxing two weeks off. But when something like the cinema shooting happens, and children die, and indeed James Holmes, only 24, not long an adult himself, is the perpetrator you have to stop and think.

Are we conning ourselves if we truly believe that we've become desensitised to violence? Batman is a good example. I grew up on Batman, the Adam West and Burt Ward version (and shows like Hogan's Heroes, The Brady Bunch and Gilligan's Island). Back then Batman seemed action-packed, and there was always a cliffhanger ending to lure you back the next day, and great villains like Burgess Meredith's Penguin, and Cesar Romero's Joker.

It's currently running on Foxtel's 111 Hits channel and, over the holidays, I thought the kids might like to revisit some of Mum's favourite old shows. But no. They scoffed at the cartoon-like nature of it all, the costumes, the effects. It had nothing. Now kids aren't happy unless semi-trailers are being overturned by baddies wielding rocket launchers, or indeed transforming into huge arse-kicking, robot-like monsters themselves.

My husband and I were watching The Dark Knight on television the other night - and how scary is Heath Ledger's performance - and we both commented on how technology has changed filmmaking, and our expectations of what a good night out means. Sure, there are still plenty of films that don't rely on computer-generated imagery, or action, or violence to some degree, but they're not the ones packing out cinemas at midnight screenings.

I've been asking myself what can I do as a parent to limit my children's exposure to such things. Sure, I could switch off the television and the computer and only allow them to watch PG-rated films. I could ban guns and all toys that have any connection to violence - even the three little midget Navy SEAL guys we picked up for five bucks in the holidays, complete with their own flippers, kayak and breathing apparatus to make attacking the rubber ducks at bath time more fun. I could never let them watch the news again, or read a paper where photographs capture their attention, and lead them to ask questions I'm not sure if I want to answer.

But then they'd - OK, he would, my daughter is a different kettle of fish altogether (and is there an argument there for the whole testosterone thing, because how many women have committed such murders?) - find a stick, or build a gun out of Lego. Even textas, the kind that clip together, have been fashioned into bazookas at our place.

Not that I'm worried about him, not in any We Need to Talk about Kevin sort of way - and there's a truly scary movie without any CGI - but I just wonder what we need to do.

Not that I know anything about the upbringing of James Holmes. He's been described as a ''fresh-faced young man with only a speeding ticket to his name'', who grew up in the suburbs of San Diego, California, where neighbours and former classmates - ''friends are notable by their absence'', mentioned one news report - describe him as an introverted but extremely smart student.

His father is a scientist with a couple of masters degrees, his mother a nurse, he was in his high school's football and cross-country teams, liked Guitar Hero and was ''funny and accepting of everyone's faults''. His parents, Robert and Arlene, must be going through hell. The forgotten victims of it all. Asking themselves all sorts of questions about what they did wrong, what they could have done differently, what didn't they notice. They'll share the blame.

As parents we ask ourselves those questions all the time. How we could have handled things better, what else we could have done. For most of us, it's a result of little things, an incident at school, at the park, or on the sports field, a screaming match over an untidy room, or chores not done, or backchat or attitude. A result of things that don't really matter at all in the grand scheme of things.

All we can do is be the best parents we can. Talk about things like the shooting and why bad things happen and carry the whole ''there are consequences for your actions'' thing right through your child's life. If you let your children watch movies like The Dark Knight Rises, watch with them, talk about what's happened, distract them occasionally, take them out for a milkshake afterwards, reiterate at every opportunity that things like this are entertainment, no real reflection on life. If they play computer games where they're shooting people or squashing them with tanks, make sure they occasionally play games where they're snowboarding or making pancakes or playing mini-golf.

Tell them you love them every day. More than once. Hug them. Kiss them.

One of the most heart-breaking paragraphs I've read about the whole thing included a quote from a neighbour of the Holmes family. ''His mother used to tell us he was a good son.'' We all like to think our own sons are too. But do we ever really know?

Twitter: @karenhardyCT