There is enough evidence to show that addictive personalties are the result of the genetic tendencies.

Those who would show detrimental addicitive personality traits will show them whether they play WoW, gamble, drink, etc.

Let's not act like letting a child play WoW creates the addictive personality, that's misleading and encourages others to refuse to recognize addiction as a disease.

The only kind of "addiciton" WoW can create is what's termed by some, "psychological dependence". It makes people feel good, so people want to do it more.

Cutting children off from WoW on that basis is ridiculous; the same dependency can be formed for religion, or reading, or hopscotch. Enjoyment based addiction is more easily broken than even an addiction to good food, which is just as well because you cannot CANNOT expect a child to only do things that aren't in any way enjoyable in order that they be able to study without distraction.

What you CAN do is enforce time management skills (using WoW or not), teaching a child to prioritize both things he wants to do and things he needs to do.