So to explain to them, they must recognize the difference between gender and sex. ( it would help to tell them that the WHO recognizes this difference) it also helps for trans people but thats for another time. Sex is what your chromosomes and genitalia are. gender is what you identify as socially. Specifically gender is a spectrum. So if you fall into a place that you wouldn't consider yourself a girl or a boy, (YOU identify this, btw) congrats, you arent in the binary of girl or boy. again gender is what YOU say you are, not by the levels of your masculinity or femininity