MS HB1391

Prohibits students who are biologically male from participating in interscholastic or intramural athletic teams designated for females at public schools, universities, and junior colleges that are members of MHSAA, NCAA, NAIA, or NJCAA.

Requires athletic teams to be designated by biological sex as "males/men/boys," "females/women/girls," or "coed/mixed" based on internal and external reproductive anatomy, endogenously produced testosterone levels, and genetic makeup.

Protects educational institutions from complaints, investigations, or adverse action by government entities, licensing organizations, or athletic associations for maintaining sex-separate athletic teams for female students.

Establishes private causes of action allowing students to sue schools for deprivation of athletic opportunities, retaliation for reporting violations, or bodily privacy violations in sex-segregated facilities, with a two-year statute of limitations and entitlement to monetary damages and attorney's fees.

Provides schools and institutions with a private cause of action against government entities, licensing organizations, or athletic associations that take adverse action in violation of the act.