性同一性
The Yogyakarta Principles, a document on the application of international human rights law, provide in the preamble a definition of gender identity as each person's deeply felt internal and individual experience of gender, which may or may not correspond with the sex assigned at birth, including the person's sense of the body (which may involve, if freely chosen, modification of bodily appearance or function by medical, surgical or other means) and other experience of gender, including dress, speech and mannerism. Principle 3 states that "Each person’s self-defined [...] gender identity is integral to their personality and is one of the most basic aspects of self-determination, dignity and freedom. No one shall be forced to undergo medical procedures, including sex reassignment surgery, sterilisation or hormonal therapy, as a requirement for legal recognition of their gender identity." and Principle 18 states that "Notwithstanding any classifications to the contrary, a person's sexual orientation and gender identity are not, in and of themselves, medical conditions and are not to be treated, cured or suppressed." Relating to this principle, the "Jurisprudential Annotations to the Yogyakarta Principles" observed that "Gender identity differing from that assigned at birth, or socially rejected gender expression, have been treated as a form of mental illness. The pathologization of difference has led to gender-transgressive children and adolescents being confined in psychiatric institutions, and subjected to aversion techniques – including electroshock therapy – as a 'cure'." The "Yogyakarta Principles in Action" says "it is important to note that while 'sexual orientation' has been declassified as a mental illness in many countries, 'gender identity' or 'gender identity disorder' often remains in consideration." These Principles influenced the UN declaration on sexual orientation and gender identity.