Not at all, said Michael Thompson, psychologist and co-author of the best-selling book “Raising Cain: Protecting the Emotional Life of Boys.” It’s normal, he explained, for boys to be interested in what men do, and in whatever it takes to be strong and powerful like their dads and the other heroes in their lives.
This is a good article for parents of young boys and how to talk to them when they want to "shoot" with toy guns or other things found around the house. It doesn't mean that they will grow up to be violent adults. One caution is offered by Thompson in the article:
When parents should worry, he said, is if their boys lack empathy, seem to really want to hurt others and are not remorseful after accidentally or intentionally hurting another child.