Ok so if the dog is done growing at 6 months then why not spay? My toy poodle stopped growing at 5 months of age. Per the advice of my vet I had her spayed at 8 months.
What happens if you dont want your pet to go into heat because of the risks of getting pregnant and having unwanted puppies,

I know that there are precautions to take but not every pet owner is responsilbe, can you imagine all the unwanted dogs out there if all vets recommened that pets be spayed after thier first heat?
I had my beagle spayed at 6 months of age and she still continued to grow to a normal size beagle, Ive had all of my cats spayed at 6 months of age and all of them continued to grow into full adult cats.
Ive always had animals (small and large) growing up and we always had them spayed/neutered at a early age and none of them had any issues not growing or did any of them end up with any kind of cancer. SO Im not quite understanding that theory.
I will have my new baby neutered at 6 months of ago unless my vet says to otherwise.
good luck with your decision.