dominance?

Question
Hi, I have a six month old male german shepherd who is not neutered yet,(I've heard it's better for healthy growth to wait a little).  I wanted him as a pet but also for home protection, my husband works nights and we love him very much but he does have one problem I'm wary of.  If one of my two young boys, 3 1/2 and 1 1/2, gets into his "space" by getting in his face or petting him when he's sleeping he lets out a low short growl and get up to move. It doesn't always happen, but when it does I correct him by giving him a jerk with his training collar telling him NO and making him submit to the boys by laying on his side until he is calm about it and then the boys pet him. This is my first GSD and I'm not sure if this is common for them as they learn their place in the "pack" or am I looking at a problem with aggression?  I'm a firm believer that dogs are a forever commitment, but I can't put my children in jeopardy. Thank you in advance.
Angela

Answer
The key to most behavior problems is approaching things using the dog's natural instincts.  Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog.  Life is much easier if the 2 legged pack members outrank the 4 legged ones.  You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/  For more on being top dog, see http://www.dogbreedinfo.com./topdogrules.htm  Poke around, that site has some additional material on dogs and children.