Gender nonconformity

Gender nonconformity (also called gender nonconforming, GNC, or gender atypical) involves not conforming to a given culture's gender norm expectations. Gender nonconforming is a phrase for someone whose gender expression doesn't match their society's prescribed gender roles or gender norms for their gender identity. Gender nonconformity transgresses societal or psychological expectations for perceived gender assignment, through presentation, behavior, identity, or other means.

A person who is gender nonconforming may or may not consider themselves transgender, or even LGBT at all. Gender nonconformity is a broad term that can include transgender as well as cisgender people.

Gender nonconforming children
Although some people apply this label to themselves, one common use of the label is when adults use the label "gender non-conforming" for children, in order to avoid outlining a child as having a particular gender identity or sexual orientation while still young. The phrase "gender non-conforming" is used to include children who are called tomboys. For another example, the label is used for a child who was assigned a male gender at birth and prefers giving what is seen as a feminine gender expression. The child's family use this label so as not to outline whether this particular child might grow to self-identify as one of any of these:
 * A transgender woman
 * A feminine but still cisgender gay man
 * A cisgender heterosexual man who just happens to be feminine
 * Even just a phase of enjoying feminine expression in childhood, which the child outgrows

Since it's not possible for the adult family of the child to predict what that behavior might specifically mean for that child's identity, they use an open-ended label. That said, it's common for people to feel very clear about their gender identity and sexual orientation from very early childhood. A child knows their own identity better than the adults around them, but doesn't have all the words for it.

History
"Gender nonconforming" was among the 56 genders made available on Facebook in 2014.