I can't believe any parent would allow their child to play COD online, especially with a microphone/headset. If you are, either you have no clue what your child is being exposed to, or you don't care. Changing the graphics settings to avoid the gore (which isn't much to begin with) is fine if you prefer that for your child, but there is pretty much NO WAY you can avoid having your child view the cartoonish "player art" of (very graphic - dripping female genitals for instance) pornography, racist/sexist/religious intolerance displays of users "Playercards" or to mute every player during every minute of every game online. Your child would have to constantly press the mute button each time a player joins the game/lobby (a player quits and a new player will take their place), which I doubt they will do (maybe only when you are in the room or can hear what's being said). The amount of filth, name-calling, harassment and just out-right mean comments by other players (even toward young children, as they have no shame) is not something that a child should be subjected to. NO CHILD should ever be permitted to communicate with strangers online without a parent hearing what is being said at all times. Would you throw your child into a room with a group of 16-30 (on average) year old strangers and let him/her talk to them? It's no different. I am an avid COD player. I play on a daily basis and have for a long time now. This game is for adults, not children. The online environment is hostile and not appropriate for children. I would not even approve of my 16 year old being subjected to the language and the graphic displays of racism, porn (MANY drawings of penises entering vaginas, oral sex, dripping genitals, "fisting", "scat", etc.), religious intolerance, hate messages, etc. that are openly displayed on COD online. Any parent who has bought this game for their child needs (their head examined) to spend a few hours every day for about a week online talking to other players and you will find out just what it is that I'm talking about. I can't imagine why any decent adult would subject a child to this type of behavior willingly. I have come across children as young as 8 years old playing this game with adults and communicating with them, telling where they live, their name, etc. and that is unacceptable, let alone how adults have called children names, made comments about how their mother is a whore, how they perform oral sex on their father, etc.
Studies have shown that children who have been exposed to violent video games show tendencies of a "lack of apathy towards others and express more aggression". It's no wonder.
I have my credentials in early childhood education, a degree in criminal justice, I am a former law enforcement officer, I am a parent/grandmother, and an avid gamer. The game is fun for adults, but not for children. Play it yourself, or you can ask any mature adult (with some morals) who plays the game about what is said/seen in this game.
If you bought this game for your child and you're permitting them to play online and interact with strangers ...you're out of your mind.