How Title IX's term 'sex' is interpreted determines whether transgender students are protected from discrimination or whether schools may set rules based on biological sex.
A 1972 federal law that bans sex discrimination at schools and colleges that get federal money, including in sports programs.
Title IX governs eligibility, funding and opportunities in school sports, making it the key federal statute in disputes over who can compete on female teams.
Schools and colleges that accept federal funds must comply with Title IX or risk losing that money following an investigation by the U.S. Department of Education.
The Department of Education issues regulations interpreting Title IX, and those interpretations can change from one presidential administration to the next.
Students and advocacy groups can sue under Title IX, and federal courts ultimately decide how the law applies to disputed practices.
A look at the state laws, federal statutes, and constitutional questions behind a debate now headed to the Supreme Court.
Read the guide →State laws restricting transgender participation in female athletic categories are headed to the U.S. Supreme Court amid competing claims about fairness, inclusion and civil rights.
Read the brief →