To determine whether your child can play Xbox 360™ games with other players on Xbox Live:
Start from the System area of the Xbox Dashboard or—if you're using the Xbox 360 system for the first time—from the Initial Setup Complete screen. Select Family Settings, Xbox Live Controls and sign in using the password for your Microsoft Passport Network account.
Note
When you sign in, the system will load your child's profile (or, if there is more than one child profile, you'll be able to choose from all available child profiles). But the Passport Network account password you will need to provide is your own.
Select Online Gameplay, Xbox 360 Online Games.
Choose one of the following settings:
Select Allowed to allow your child to play Xbox 360 games with others on Xbox Live.
Select Blocked to block your child from playing Xbox 360 games with others on Xbox Live.