Florida has become the latest US state to ban transgender girls and women from participating in female sports at public schools and colleges.
The state’s Republican governor Ron DeSantis signed the measure into law on Tuesday.
The law says women and girls must play on the teams of the biological sex on their birth certificate.
LGBT activists have denounced the move as “discriminatory”, with one group vowing to launch a legal challenge.
“We believe that is very important that the integrity of these competitions are preserved,” Mr DeSantis said as he signed the law at a Christian school in Jacksonville city.
“We’re gonna go based on biology, not based on ideology when we’re doing sports.”
The move comes as Republican-led states push back against pro-LGBT policies supported by the administration of Democratic US President Joe Biden.