When I was a little kid, we had a maltese and a yorkie. They were such a big part of my life, I can't imagine having grown up without them. That being said, not all kids are the same. Some kids are rough or wild or even just clumsy and can hurt the yorkie on accident. You just have to be very careful. My yorkie actually loooves children so much. He's a bigger yorkie at 11lbs, but our nephews and niece know that they are not allowed to pick him up. He loves when they play fetch with him and run around with him
Just yesterday, we stayed with a friend of ours and she has an 8 month old baby. He loved her, and wanted to be with her the whole time. She was petting him and being gentle, and he was happy as can be. When she went to sleep, he layed at the edge of the bed as if he were watching her. Everything was about the baby with him yesterday
But yorkies should never be with a child unsupervised, not because the yorkie will hurt the child, but because the child can injure the yorkie.