Heteronormativity is the belief that everyone is heterosexual by nature, and every other form of human sexuality is not as good as heterosexuality, or even an illness that needs to be fixed. In a heteronormative system, there are two strict genders, men and women, and everyone must behave according to their gender role in society. A heteronormative view of the world believes that a person's sex decides their sexuality, gender identity and gender roles.

Homophobia, transphobia, and heterosexism could not exist without heteronormativity.

According to queer theory, societies force heteronormativity on people it does not fit, such as LGBT people, queer people, and intersex people.

Where the word comes from 

Michael Warner made the word "heteronormativity" popular in 1991 in one of the first books on queer theory. It came from Gayle Rubin's idea of the "sex/gender system" and Adrienne Rich's idea of "compulsory heterosexuality." According to Samuel A. Chambers, heteronormativity shows what societies expect, demand, and allow when they consider relations between men and women to be the only normal ones.

Discrimination 

People who argue against heteronormativity include Cathy J. Cohen, Michael Warner, and Lauren Berlant. They argue that it holds down those who do not fit it, marks them as outsiders, keeps them out of society, and makes it hard for them to express themselves. Heteronormative policies and institutions strengthen the belief that people are heterosexual and that there are only two genders and sexes by nature. They argue that heteronormative culture gives an unfair advantage to heterosexual people (this is called heterosexism). It causes members of society to keep LGBT people out of work, school, and the greater society, sometimes using the law.

Against gay, lesbian, bisexual, and transgender people

According to the cultural anthropologist Gayle Rubin, heteronormativity ranks sexual practices from "good sex" to "bad sex." This "sex hierarchy" ranks sex between two married heterosexual people for the purpose of creating a child as "good," and ranks people and acts that fall short of this standard lower until they become "bad sex." Gay couples who are married are somewhere in the middle. Gay people who have sex with many partners are also in the middle, but below gay married couples. Patrick McCreery, a lecturer at New York University, believes this is the reason why gay people are attacked for doing things that straight people also do, such as watching pornography or practicing BDSM.

McCreery says that this "sex hierarchy" also exists in the workplace. Gay, lesbian, bisexual, and transgender people are more likely to be kept out of work the lower they fall. Transgender people fall especially low in the hierarchy and face the most obvious discrimination. This leaves many LGBT people without jobs. People can be fired for being LGBT, or they can never be offered a job for the same reason. In 1991 the restaurant Cracker Barrel in the United States made the news when it fired a lesbian worker. There was no law against this, and there is still no law against it in most of the country.

Against intersex people

Intersex babies can be born with neither a penis nor a vagina. Doctors and parents often force intersex children to have surgery to make them look more like most men and women. Usually they are healthy without this and it is not necessary. Most intersex children are not allowed to decide if they want this surgery. This is not because there is anything wrong with their bodies. Rather, parents are often afraid that their children will be judged. In other words, doctors and parents force them to have surgery for social reasons, not biological ones.

Sources

Discrimination
Sexuality
Society