Yorkie temperament is similar to that of other terriers – this little dog not only wants to be in charge, it will be in charge. Nothing sways it from its self-appointed superiority, not a Great Dane or a Rottweiler or a wimpy owner. He can be scrappy with other animals, manipulative if not trained, and stubborn. Poorly-bred Yorkies can also be snappy, territorial with food and toys, and hard to housetrain. For these reasons, Yorkies are not the best choice for a family with babies or young children.
Yorkies also need more daily care than most terriers. Although it doesn’t shed much, the long, silky hair will tangle and mat if not properly brushed. Diet is important; soft foods can exacerbate problems with already weak teeth and gums.
http://www.canismajor.com/dog/yosiau.html http://www.ytca.org/