Modifies guidelines for student participation in athletic contests organized by sex

HB 1973 modifies Missouri law to require schools and colleges to determine student athletic participation based on biological sex as recorded on a student's birth certificate or government record. It prohibits students from competing in sports designated for the opposite biological sex (e.g., a student assigned male at birth competing in girls' sports), except when no equivalent competition exists for their biological sex. Schools violating this law risk losing state funding, and affected students or parents can seek legal remedies. The law includes a sunset provision, expiring August 28, 2027, and defines "sex" as male/female based on reproductive biology and genome at birth.