In order to analyze the use of the concept of sex by Brazilian courts, was chosen four decisions handed down by the Bahia Court of Justice in cases relating to change of civil registry transgender people that has been granted the right to the given name at the expense of possibility change of sex. Sexual reassignment surgery mostoru is essential for the sex change of claim in the civil registry. Finally, contacted to produce a precarious living conditions by the judiciary to transgender people, corroborating the sexuality device.