Being male or female is defined early during pregnancy. Gender dysphoria is a gender identity that occurs when genetic information does not coincide with the cerebral one regarding gender. In studies of rodents (mammals) it has been possible to demonstrate that the morphological parameters of the brain (volume of structures, number of neurons) are adjusted to the hormonal events that occur during critical periods of gestation. These rodents behave like the opposite gender in certain behaviors. At present, gender dysphoria is not equivalent to schizophrenia or autism, but is still considered a mental illness. The perception of the reality of patients with gender dysphoria is not altered. My project is aimed at preparing legal and expert reports to help modify the health care laws in this regard.