A person who does not identify with conventional gender roles or identities might describe himself or herself using the adjective transgender.
A transgender person is someone who doesn't quite fit the ideas of gender that are culturally considered "normal." Most often, someone who identifies as transgender feels that he or she was born into the wrong gender — for example, a boy who feels strongly that he is actually female. In some cases, a transgender person switches genders. The key to this word is the Latin prefix trans, which means "across," but also "beyond."