You need to consider the needs of the house first and foremost. Children that are very young, usually do not do well with any breed. They like to pull tails, poke eyes, pull ears, and all in all just make the poor things miserable. Many breeds will not tolerate this.
If you consider a puppy to grow with your child then make sure the child is old enough to go with you and bond with the puppy or dog BEFORE you bring it home. People believe that they choose the animal. Most animals chose their owners. Just because you bring a dog or puppy into your home for a certain someone doesn't mean that it is going to be that person's pet. Whoever is at home with the new addition is more than likely to have more control. It is all in how the puppy or dog was raised as to how it will behave with children.
Animals are different with everyone. Just because you own a dog or puppy doesn't mean he or she will like you or your kids. Depending on the way they are nurtured. If you want a pit bull then you need to think of the massive power they have and consider the temperament, the agility, the size, and how well you feel you can trust this animal with your friends and family.
Animals are not at all the safest thing to have regardless of the breed. All breeds have wanted and unwanted qualities. You have to research all aspects of any breed. If you want a German Shepherd you have to ask yourself some questions about faithfulness, trust, and loyalty. These animals are known protectors. Pit Bulls are known for brawn. They are muscular, Shepherd's are smart.
If you want a pet - then you don't really need a dog . They are companions, are part of the family. They need to be taught things that are appropriate for all aspects of their life. If you want to take this dog on family outings with the children then you need to socialize its skills for that purpose.
Considerations need to be for all aspects of you, your family, the animal in question and most of all, how do you want your companion to mingle with the rest of the world. Any and all breeds fit somewhere, may not be your home or mine but they do fit somewhere. Be considerate of the animal you choose. Don't get a Labrador if you don't have the room and time to take care of him or her because they will bite too. If you are not happy you lash out; most of the time when an animal lashes out there IS a reason. Some I know have turned, but why. If you dig deep enough you will find the reason. Please consider all aspects. And DO research before you take on this endeavor.