Title IX states:

"No person in the United States shall, on the basis of sex, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any education program or activity receiving Federal financial assistance."

biological females are being denied the benefits of fair competition by having transgender students compete in this way.

the same way we are seeing three bathrooms in public facilities there need to be 3 divisions ~ or you are effectively denying biological females the chance to excel / win in their respective sports.