The term “transgender” refers to a person whose sex assigned at birth (i.e. the sex assigned by a physician at birth, usually based on external genitalia) does not match their gender identity (i.e., one’s psychological sense of their gender). Some people who are transgender will experience “gender dysphoria,” which refers to psychological distress that results from an incongruence between one’s sex assigned at birth and one’s gender identity. Though gender dysphoria often begins in childhood, some people may not experience it until after puberty or much later.

https://www.psychiatry.org/patients-families/gender-dysphoria/what-is-gender-dysphoria

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