I know some will say not to have 2 puppies at the same time and not to have 2 females or 2 males at one time. Well, I'm here to tell you that I have now and have done in the past all of the above and I have never had any problems or regrets. My girls are sisters from the same litter and they are so bonded...I can't imagine them not being together. They are now 3, both were spayed at the same time when they were around 2 1/2 and we have never had any aggression or issues of any kind. My boys (unrelated but neutered) have never had issues either.
I know others have their own experiences to share but there is mine
Good luck with your decision.