I had a 4.5lb yorkie named Henry before I got married in 2000. Everything went grand until we had children.
Henry had a hard enough time adjusting to Lisa (my wife) but he did not do so well when we had Jared in March 2002. Once December 2002 rolled around, Jared was crawling, and Henry bit him on the hand. Needless to say - DOG GONE! He lives with my best friend and has not had any real issues (but their children were older). Funniest thing was when I was telling my parents about what happened, my mother was more worried about the dog than she was her own grandson. To this day, Jared is VERY AFRAID of dogs, and vividly remembers being bitten (we don't re-inforce it, he just brings it up anytime a dog is around or mentioned).