She's definitely a female. They've locked about 4 times now. No other males in the house. He calmed down a bit when we held him, but put him back in his cage as he started thrashing in our arms. He's quiet now.. but we are a little concerned about the behavior. Also, his cage was freshly cleaned, and it was another females old cage. We switch them around sometimes to encourage feeding, so I don't think he was smelling male in his cage when we took him from the female.