Medicalization refers to the treatment of transgender identities as a medical condition, such as through diagnosis as Gender Identity Disorder or referring transgender people to psychologists as a standard part of their treatment.
In some ways, medicalization can be beneficial to transgender people, as it can help grant access to medical transition procedures. The existence of Gender Identity Disorder prevents these procedures from being viewed as elective, and instead they are often required to be made accessible through one's insurer or healthcare provider.
However, because gender identity is an internal experience, it cannot be reliably diagnosed. Medicalization often results in the implementation of gatekeeping in order to "prove" diagnosis, such as expecting transgender individuals to socially transition and/or strictly follow gender roles associated with their identity in order to gain access to treatment.