Adolescence is a time of rapid brain maturation that is partly influenced by sex hormones. In this project, magnetic resonance imaging will be used to assess the influence of sex hormones on brain structure and function. Malvina Skorska will examine how the brain structure and function of adolescents who experience gender dysphoria (i.e., adolescents who experience themselves as the other gender) differs from that of adolescents who do not experience gender dysphoria. She will document how the adolescent brain responds to sex hormone therapy. Some adolescents who experience gender dysphoria utilize sex hormone therapy. Because sex hormone therapy directly influences the sex hormones that are already in the body, this project will provide insight regarding how sex hormones affect the adolescent brain. Surprisingly, even though sex hormone therapy is widely used to help adolescents who experience gender dysphoria change from one gender to the other, its impact on the brain is largely unknown.She will also examine a very popular biological explanation of gender dysphoria, namely, that brain development is shifted in the direction of the other sex. Additionally, she will investigate whether there is a relationship between the structure of the brain and patterns of brain activity, as well as whether brain structure and function change together during sex hormone therapy.