I personally prefer to play an adult avatar my same age irl. Although I did seek for a sl family and found a real connection with a few people there some of my best friends now irl and sl. I thought it would be kinda cool for the rp to age up into an adult every 3 months my avatar ages im now rping at age 16 and ill stop ageing when i hit 24. I can't really stand babytalk and an abundance of gestures. I think that is why I don't like child avis that much. Other than that I feel most people who play children probably use it how most people use roleplay to experience something they can't irl. A Lot of the child avatars I have met didn't have much of a childhood. Either they were forced to grow up too fast or just didn't have a good one. Sl gives them the chance to re do that portion of there life ..give them a second life.. I personally don't see anything wrong with it as long as they are not breaking any TOS.