thinking about a new pup??????

Question
I am the owner of a 2yr old german shepherd, i love him and he is a great dog, super friendly, great with children listens well, gets along with the cat, he is really a doll, my daughter has been asking for another dog she wants to get a small breed dog, a pug, or boston terrior, and i have been thinking about it, but i dont want my GS(lucky) to feel left out, he is the first dog i have ever owned and i dont know how they are with other dogs moving in, people are telling me if i get another dog he may turn aggressive, but i just cant see him that way, he gets along with all other dogs we rung into on our walks and my cat, he has never even growled at anyone/thing, so anyone who has any thoughts to help me decide, or any recomendations for what type of small breed dog he may get along with best, please tell me what to do, i am so in the air, i really dont want to upset my dog, but i would like to have a small breed dog as well, we have a big home and lotsa land, any suggestions would be great thank you heather,
levittown PA

Answer
Having a new dog move in will upset him, but he should get over it.  The better leadership you are giving him, the better it will work.  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

Select a female.  Usually a male and female will get along fine.  continue to give him plenty of attention.  
Finding a good breeder and purchasing a puppy that will make a good pet is very difficult.  Almost nobody is intentionally breeding dogs to be nice pets.  Most of your so called reputable breeders are breeding for show or something.  They may say the puppies they don't keep for their purpose make great pets, but the truth is that the parents were selected for other than health and temperament.  Often they keep the puppies in the kennel too long and they miss the important early socialization puppies need to live in the house with people.

Next are the disreputable breeders.  They breed any 2 registered dogs they can lay a hold of looking only at the money they can make selling them to pet stores.  Pet store puppies are easy to find, but difficult to socialize into nice pets, perhaps difficult to even keep alive.  You will not get what you pay for at a pet store.

One of the best sources for dogs with a predictable personality is the rescue
dogs.  These are dogs that lost their home, but were taken into a foster home
to be retrained as necessary and placed in the right home for them.  You may
find a rescue near you starting at http://www.akc.org/breeds/rescue.cfm  The rescues charge a fee to help cover their expenses, but is much less than the price of a puppy plus all its medical expenses the first year.