Is it advisable to get a dog when children are around the age of 3? How do pets help to enhance a child's growth?

So I have a dog, a cat and a newborn at home. It's a zoo for sure but it's a house that's full of noise and love. Kitty, doggy and baby all get along. In fact our dog takes it as his responsibilty to protect our newborn and gets very upset with us if we don't tend to her when she's crying. There was an incident where I was attempting to let her cry it out for a few minutes (while sitting on the bed with her), but just not immediately soothing her as I am prone to do. Doggy started barking at me and tugging at my dress to get me to go and look at her. When it realized I was not about to do anything, he took it as his responsibility to go soothe her, and jumped on the bed and nuzzled up close to her as if trying to pat her back to sleep! How amazing is that? So pets and kids - absolutely in my books!