Male to female gender identity disorder (MTF/GID) is a rare condition. Such patients tend to complain that their speaking fundamental frequency (SFF) does not fit because it is too low. Type 4 thyroplasty (TP4) conversely increases the pitch of the SFF as the tension of the vocal fold is tightened causing the SFF to become high-pitched. While vocal pitch disorder is not life-threatening for patients with MTF/GID, it can cause substantial worry and stress. TP4 can therefore improve the quality of life of patients with MTF/GID.
