Periods. Use them.
But really, I don't see a problem with it. In my experience, kids act with similar intentions regardless of what medium they use to express them. In other words (which are not actually my words, though I don't remember who's they are), if you take a kid's toy gun away, he'll pick up a stick and keep shooting at make-believe bad-guys.
The violence in inherent in the person, and that's ok. The aggression simply needs to be tempered by education and empathy.
dante brevity said:
I know that my kids won't be playing violent games until their teen years, maybe 14 or so.
Yes, I can see the logic in that. First make it taboo and mysterious by denying it from them, then suddenly and arbitrarily let them have it
at the very moment their bodies are jumping between hormonal extremes. This must be why teens handle sexuality so maturely and responsibly.