It takes quite a while before you know what the sex of a RT is. They need to be about 5" in length before truly knowing the sex. That will take 5 yrs or more. What you think is a female may very well be an inmature male. I have known of people who thought they were for sure with a female. Then BOOM the tail grew long and thick, curving to the side.
Your RT's will start reacting differently towards one another if you have the opposite sex together when thet are of age. You will not be able to mistake it. The male gets very abusive when he wants to mate, head bobbing, and ramming occur. If you have the opposite sex housed together right now, you wont have to worry about that for a long time..........
Now mating is something mine had to practice at for 3 years before babies came. It is not something easy for them. The female has to be still long enough for the male to get positioned on her and connect, finish, and climb off. My guy landed on his backside many a time!

My female got quite a few bites on her legs too.