I have a 7 year old daughter and have never had any problems with her and the dogs. She has lived in a house with a small dog since the day she was born and has had it drilled into her head how to handle them. (And as I found out yesterday she can put up a topknot better than I can!
)
I would not want an extremely small Yorkie with her though...just because I'm paranoid and stay nervous enough when it's just me around our little 3 pounder.
I think it depends on the child and the dog.