As a High School Chemistry teacher (10th-12th grades), I would suggest this game for a family with teenage kids. I feel that at your children's age level they should be able to take in information, analyze it, determine the appropriate-ness of it, and choose a response based on what they reasoned. I would keep them away from the forums if you do not want them involved with petty bickering, of which I too am a part. If you are going to be playing the game alongside them, I see no reason why they cannot play. Of course you would want to pick out the community you all associate with in game, but also realize that online interactions are always dynamic and you cannot fully predict what will happen. When something that you do not particularly like does happen, you could use that time as a "teachable moment" to educate your children about what happened and have a discussion on why it is or is not an appropriate action.