Nah that's an old myth.. Puppies and kittens are regularly spayed/neutered at 8+ weeks now.
We get our puppies spayed/neutered when they are in for their earcropping at 8 -9 weeks of age.. Been doing it for 12 years and not a problem at all..
Works out much better actually, they are concentrating only on being your companion, rather than other dogs, dominance issues, breeding etc.. Plus there is less problems with male /male aggression etc. Plus in the case of the Doberman, they only have to have that one surgery, rather than one for ears and then back later for neutering/spaying... it's all done at the same time and works out better. Plus it insures the responsible thing is done!
We actually do the microchipping also when they are there for spay/neuter.. They don't need to be put under for the microchip.. The needle isn't that big.. It's somewhat bigger than a regular vaccination needle, but it's not the size of a pencil or anything.. I have never heard of a vet putting them to sleep for a
microchip.. That's a little weird.
Edit: they actually recover MUCH quicker when they are spayed/neutered at 8 weeks or so.. They don't miss a beat, come home, eat drink play and you wouldn't even know they had surgery, if they didn't have one tiny wee stitch on their belly.