The number one concern any parent should have concerning airsoft guns is the safety of their child. Their first question should be "how safe is this gun?" Overall, airsoft is a safe and enjoyable sport, but that is only because strict rules are enforced toensure all players are safely conducting themselves.
The most significant danger presented by airsoft guns is the possibility of being shot in the eye, the most vulnerable part of the body in an airsoft match. If you're going to buy your kid an airsoft gun, make sure you also buy them a full face mask. Sure, you could just buy them goggles, to protect just their eyes, but getting shot in the forehead or neck is never fun, and you should want your kid to be as safe as possible.
Minimum engagement rules should also be enforced. Airsoft fields around the United States require guns that shoot at 400 fps or more have a minimum engagement distance of at least 100 ft or so. Airsoft guns that shoot .20 gram BBs have at least a 10 to 20 ft engagement rule. Keep in mind the minimum engagement distance may change slightly depending on the field you visit. These rules are in place to ensure that no one is hurt while playing the game.
There are many more rules and safety concerns you should be aware of, so it's your job, as the parent, to do your due diligence and research this subject thoroughly before buying your kid an airsoft gun. Thanks for the above, airsoftsation.com