Hi Shannon It really doesn't matter what sex your birds are if one is bullying the other. It has nothing to do with the sex sometimes. I had two males and one was a bully and I separated them immediately so the victim wasn't so stressed and would not get hurt.
Once it starts it will not end even with a bigger cage...been there done that. I bought a huge flight cage and Tom continued to bully and in fact it got worse as time went on.
Good luck and please be observant if it is a regular problem, you need to act to stop it. Put the aggressor in the smaller cage alone with toys, and it will immediately relieve the victims stress.