Gender identity is the extent to which one identifies as being either masculine or feminine, and is often shaped early in life.
Those that identify with the role that corresponds to the sex assigned to them at birth (for example, they are assigned male at birth and continue to identify as a boy and later a man) are called cisgender.
Individuals who identify with a role that is different from their biological sex (for example, they are assigned male at birth but feel inwardly that they are a girl, or a gender other than a boy) are called transgender.
Recent terms such as genderqueer, genderfluid, gender variant and gender non-conforming are used by individuals who do not identify as either transgender or cisgender, but identify as existing somewhere along a spectrum of genders, often in a way that is continuously evolving.
Although the formation of gender identity is not completely understood, many factors have been suggested as influencing its development, including biological factors, social factors, language, social and economic power, and social learning theory.
According to proponents of queer theory, gender identity is not a rigid or static identity but can continue to evolve and change over time.
Social learning of Gender-role development