Sidonie Csillag is the young homosexual woman patient, an account of whose treatment Freud published in 1920. The treatment of five sessions per week lasted six months. However, it remains, even in Freud’s own opinion, a treatment marked by the impossibility of any encounter with the adolescent girl. We will re-investigate this non-encounter in the light of queer theory and Gender Studies. We will see how issues of gender and queerness can interest psychoanalysis, particularly in relation to the treatment of adolescents.