Society takes our biology and uses it to divide us into two distinct binaries to create power. Because if one has a penis, he is a man. Another has a vagina, so she is a woman. Therefore, if one is strong, by definition of binaries, the other has to be weak, there is no third option. And for the sustenance of the power, we have these distinct norms associated with the two cis genders, like pink for girls and blue for boys, etc. Anything out of the two is at the bottom of the power pyramid. So, to conclude, apart from our biological organs, we do not have a particular 'gender' at birth. We have sex which is used to bifurcate us and make us more feminine and masculine with distinct traits to rule or be ruled. Being non-binary, for some, is a state of being. That is who they are and they choose to not conform to the binaries. That is their way of breaking free of these rigorous traits assigned to us by society due to our genitals.