Sex is one's anatomy. Gender is how one identifies. Ruby Rose, for example, is gender-fluid, and now knows she doesn't wish to change her anatomy; she is NOT trans. Gender-fluid people don't care to change sexes because we're happy with our bodies; we're fine with our anatomy. Our genders, however, can change from being male, female, neither, or both. It depends on the person. Transgendered people wish to change their sex, and that is what makes us different. It can be confusing sometimes to people who don't know what it feels like.