I think it depends on the dog's behavior and the owner's personal preferance. Undescended testicles still "work", as far as I know. I've never had female dogs, and the boys have all been just fine, "fixed" or not. I have not noticed any big differences in behavior. My last two pups were neutered because they came from SPCAs and it is required.
That's all I know. Not much help now that I think about it. :?
That's all I know. Not much help now that I think about it. :?