Is a child is exposed early on to what a firearm is and what its use is, they will become so accustomed the entire concept of shooting that they will be desensitized to it later in life. In America especially, people are likely to eventually be exposed to firearms, but being raised around them will cause problems.
Simply being exposed to firearms does not make a child more likely to be violent. If a child is exposed to firearms at an early age and is taught to respect the firearm and how to responsibly handle a firearm, I believe it would make them less likely to engage in violent behavior. If a child is taught shown what a weapon can do, the power of the weapon becomes real to them. If a child has never been shown a real weapon, their only exposure is likely to be movies or video games. These mediums tend to glamorize guns and make it seem like fun or a game. I believe it is much healthier if it is demonstrated to a child that: this is a weapon, this is what it can do, it can be dangerous, always be safe, never use it to harm someone unless you absolutely have to. Therefore, exposure to guns, if done correctly, can actually reduce violent behavior.
No, a I don't believe a child's exposure to firearms has any correlation at all to violent behavior. I think instead that a child's exposure to violent behavior correlates to violent behavior. A firearm by itself does nothing to promote violent behavior. A child who is exposed to violent behavior as they grow up will tend to carry on in the same tradition. Huge difference between growing up in a family where the dad hunts wild game, and growing up surrounded by violent, armed, street gangs.
I think a child's exposure to firearms correlates with their violent behavior being more deadly if and when they do decide to act out. The reasons for this are obvious; guns are killing machines. They were designed for nothing other than ending a person or animal's life, and that's the truth.