The term "transgender" has been developing since the 60s, and ever since its meaning has undergone a long period of expansion and categorization, it has slowly developed to an umbrella term.
The transgender is of particular importance to the challenges towards the categorization of the identities in queer theory. When we speak of the transgender, it includes those who dress in one's (trans)gender and those who opt for sex-reaffirmation, as well as the people who do neither but just likes living the life in a manner unlike their assigned genders.