I would be more concerned abouth the weight differences than the gender issue. Even if your orig-a-pup (original pup)
was gentle the size alone could cause the Yorkie to be injured. I am looking for an adult Yorkie companion for my 3.6 lbs Yorkie who is going to be a year old next month, and I was told to only get a dog no larger than 5 lbs to be on the safe side by our vet. Guess they see unintentional injuries when there is too much weight disparity.