Hi Guest
It all depends ..... on the individual dogs, the owner and the situations.
If you are an experienced owner you may find that you can handle 2 bitches fine. It may be "safer" to go for a dog, I had a dog and a bitch and they were great pals, never a cross word between them.
Many owners do have 2 bitches and have no problesm. If you undersrand the pack system and how dogs think you would probably be fine with 2 bitches, especially if the second one was in troduced as a puppy.