Well! At times, it is dog's way of showing love, but this way they also show dominance over the human. And it is not advisable to let the dog lick your baby's face because the baby is too small, and dog will take over her and will show dominance. And he may get over the baby if you are not around, which can be dangerous as baby can also get hurt. http://www.dogsandbabieslearning.com/2011/12/03/should-dogs-lick-babies/