The current work defends the possibility of altering the civil register of transsexuals, so that it presents the name and gender appropriate to their claimed gender, even in the cases that sex reassignment surgery was not performed. Through a concept of transsexuality as an identity experience rather than a pathology and understanding gender as a complex concept, involving factors of physical, psychological and social order, the possibility of sexual selfdetermination is viewed as a constitutional right. Using a civil-constitutional hermeneutics, it is possible to allow a greater privacy and autonomy in relation to self-referring matters, especially in a State that have as its main pillars of it’s legal system the plurality and dignity of human beings. In this context, being gender identity one of identity components, allowing the right bearer self-determination, in a responsible and conscious manner is fully possible, even with the lack of a formal law regarding it, being it in fact a health right, in relation to its psychic aspect. The constitution, by creating a catalog of fundamental rights, assures private autonomy, allowing each one to decide about its life in matters regarding existential situations in a manner that fulfills its aspirations and values.