It is important to understand the difference between sex and gender. A
person's sex is assigned soon after birth based on their external gentitalia.
The sex marker, male or female, that is chosen by the doctor, stays with them.
This assigned sex dictates that individual's clothes, toys, and jobs, what
behavior is considered appropriate and every other aspect of their life. Many
people do not see a problem with how much their life is influenced by their
assumed gender and life on without questioning it.
For people who are not cisgender, their assigned sex does not match their own
identity— they are unable to fit into society's traditional gender model.
This model is explained by Susan Stryker in
Society believes that everyone fits into these two categories. Either:
You are born male. You are masculine. You identify as a man. You are attracted to women. Or,
You are born female. You are feminine. You identify as a woman. You are attracted to men.
* For gender and sexual minorities, this model does not hold true.
Not all genders are binary...
Gender is often thought of as a binary, being either male or female. The most well-known
identities in the trans* community are transsexuals— either male-to-female (MTF) or
female-to-male (FTM)— who live full-time as the gender "opposite" their biological
sex. Transmen and transwomen still have binary gender identities. There are many non-binary
gender identities that are less understood and often overlooked. Two examples of non-binary
gender identities are genderqueer and gender fluid. Genderqueer people often don't identify
with being male or female; they may identify somewhere in between these two genders or off
the gender spectrum completely. Gender fluid people experience gender differently on
different days; they may have masculine days, feminine days or androgynous days. Gender
fluidity can be explained as a shifting of gender or movement along the gender spectrum.