German Shepard - HELP!!?

Hi! I am looking to purchase a German Shepard, as I love the breed. I have a family with 3 young children and want a dog who will be good with them as well as protect my family as a guard dog. I am scared, however, about the health concerns that surround the dogs. Does anyone have advice from owning a Shepard? How often do they get sick? What diseases have they gotten? Etc. All advice welcome & wanted!!