The Giant Schnauzer is still very much a working, guarding breed and therefore better suited for those with older children or teenagers. As puppies and juveniles they are big, boisterous and bitey, not an ideal combination with children. This is also a dog who requires several hours exercise and training per day which will take up a reasonable amount of time and energy making them less suitable for the young, busy family.
While many dogs are traditionally thought of as being good with children, all dogs and children need to be taught to get on with each other and be safe together. Even so, dogs and young children should never be left alone together and adults should supervise all interactions between them.