My Diesel isn't neutered, he's 6, and he probably never will be. I would never consider breeding him. Why? I know nothing about breeding, and even if he is registered, it's a lot of responsibility. His vet told me it would make no difference in his temperament if I fixed him now, or not. He's a very docile dog, not aggressive.
I, honestly, would think about the circumstances, and the informative advice of everyone here. There are far too many dogs in shelters that need homes.