My wife's younger son in the Philippines got a Chow (crazy enough with the heat), and one of the grandsons is only nine. He can love on the dog, use him as a pillow, etc., and the dog just loves it. When we visited last July, my wife just started to reach out to pet him and he jumped at her and scratched the skin while biting her knee. Since there are so many strays in the Phils, right around the corner from the house is a "Dog Bite Clinic". She got a couple shots, a couple weeks apart.
I had told her that Chows weren't very safe to have around, but they had already had him a while. I kept trying to pet him, just by letting him rub against my leg when he would walk by. The day before we left. he was letting me pet him. I'll probably have to start over when we go thee for Christmas this year.