There is a new announcement that Title IX of the Education Amendments of 1972 now “makes clear that the federal Title IX law prohibits discrimination against transgender students.” Here are the relevant clarifications from the FAQ released by the Department of Education. While primarily concerned with addressing sexual violence, the full text concerning transgender youth says:

B-1. Does Title IX protect all students from sexual violence?

Answer: Yes. Title IX protects all students at recipient institutions from sex discrimination, including sexual violence. Any student can experience sexual violence: from elementary to professional school students; male and female students; straight, gay, lesbian, bisexual and transgender students; part-time and full-time students; students with and without disabilities; and students of different races and national origins.

and further:

Title IX’s sex discrimination prohibition extends to claims of discrimination based on gender identity or failure to conform to stereotypical notions of masculinity or femininity and OCR accepts such complaints for investigation. Similarly, the actual or perceived
sexual orientation or gender identity of the parties does not change a school’s obligations.

Indeed, lesbian, gay, bisexual, and transgender (LGBT) youth
report high rates of sexual harassment and sexual violence. A school should investigate and resolve allegations of sexual violence regarding LGBT students using the same procedures and standards that it uses in all complaints involving sexual violence. The fact that incidents of sexual violence may be accompanied by anti-gay comments or be partly based on a student’s actual or perceived sexual orientation does not relieve a school of its obligation under Title IX to investigate and remedy those instances of sexual violence.

If a school’s policies related to sexual violence include examples of particular types of conduct that violate the school’s prohibition on sexual violence, the school should consider including examples of same-sex conduct. In addition, a school should ensure that staff are capable of providing culturally competent counseling to all complainants . Thus, a school should ensure that its counselors and other staff who are responsible for receiving and responding to complaints of sexual violence, including investigators and hearing board members, receive appropriate training about working with LGBT and gender-nonconforming students and same-sex sexual violence.

Pretty unambiguous wording, which in a sweeping way now protects transgender students at any public school which receives government funding.