The expression gender binary refers to the idea that humankind can be divided into precisely two sexes, no more and no less. Something that is binary (bi=2) can assume one of two values, often denoted 0 and 1 or odd-even. One example of this is the second to last digit of a Swedish personal identity number, where odd indicates that the person’s legal gender is male whereas even means female. The view of gender as something binary defines trans persons as deviant, according to the so-called binary gender norm (see also othering). Gender binary is also a prerequisite for the heteronorm, which is the assumption that heterosexuality – that women desire men and only men, and vice versa – is natural and applies for all people (see also heteronormativity).
Linear gender refers to the view that a person’s body, personal identity number, gender identity, pronoun, name, gender expression and reproductive organs are always unequivocally masculine or feminine as well as consistent throughout life. Something linear is something that follows a line. Somebody who is in compliance with the notion of linear gender can be called a cis person (see also cisgender/cis). If you are a cis person, you enjoy a wide range of privileges such as not having to deal with questions about your genitals, the peace of using public toilets and swimming pools without having to worry about derogatory remarks and violence and the ability to pick up something from the mail office or the chemist without the person behind the counter questioning your gender or that you are the person you claim to be. The concept of linear gender is a way to describe a view of gender that implies that those who do not conform to the norm are considered problems (see also norm/norm criticism).