lots of great advice so far. i won't repeat too much of what has been said, but having 3 youngsters in a home, and then adding a rambunctious MALE puppy is not a good idea.
males tend to be more of a handful anyways; at least my male is usually always in play-mode and he is 3.5 years old (never going to grow up apparently). my females are more relaxed and are better around kids; i think others would agree. also, working breeds tend to not realize their size and will bounce around quite a bit, knocking over your kids or lamps or pictures, etc.
children usually don't understand how to act around dogs and will pull their ears, approach them from the rear and spook them, among other things. taping and caring for a dobe's ears takes lots of time and effort; would a child understand they won't be able to mess with the posts and tape for several months until they are standing up without being posted? doubt it.
a lot of breeders won't sell a pup to a home with small children. you may be waiting several years until a reputable breeder will consider sending a pup your way. i know a breeder who won't sell males to a home with children under 10 years old.
do you have the patience to teach your children the rights and wrongs around a pup, as well as teach your pup his boundaries (plus crate train, housebreak, basic obedience, etc.) at the same time? lots to consider here.