The US Supreme Court on Thursday allowed the administration of President Donald Trump to implement a policy that prohibits transgender and non-binary people from choosing a gender marker on their passport.[1][2] Gender in passports is thus determined according to birth documents.[1] This ruling suspended a lower court ruling that allowed this choice.[1][2] The Trump administration reversed a 2021 Biden-era policy that allowed an "X" for non-binary, intersex, and gender non-conforming people and repealed the medical certification requirement for transgender people.[1] In addition, the Supreme Court has sided with 25 state laws that prohibit transgender participation on women's sports teams in order to protect fair competition and safety.[3][4] The judges emphasized biological differences, such as muscle mass or lung capacity, which persist even after hormonal treatment.[3] Three justices dissented, arguing that the policy would harm the plaintiffs.[2] These decisions may affect other disputes about the rights of transgender people in schools or the military.[3][4]