The principal really needs to read the law. This school is so fucked.

https://codes.findlaw.com/az/title-15-education/az-rev-st-sect-15-120-02/

The law in question only prohibits biological males from participating in female sports. It does not prohibit females from joining boys teams. Compare and contrast sections “B” and “C”:

B. Athletic teams or sports designated for “females”, “women” or “girls” may not be open to students of the male sex.

C. This section does not restrict the eligibility of any student to participate in any interscholastic or intramural athletic team or sport designated as being for “males”, “men” or “boys” or designated as “coed” or “mixed”.

I also thought this was pretty interesting:

E. Any student who is deprived of an athletic opportunity or suffers any direct or indirect harm as a result of a school knowingly violating this section has a private cause of action for injunctive relief, damages and any other relief available under law against the school.