[Serious] Non-binary

[Neo-Scholastic]

What biological binary? Even if you've never heard the term intersex, I'm sure you've heard crude references to "chicks with dicks." The sharing of physical sexual traits across your imaginary binary boundary may not be common, but it does provide evidence that biological sex is more a scale than an on/off switch [emphasis added]. 

To be clear, there are two sexes in humans—these are functional reproductive categories that exist at the group level. The affix inter- in intersex aptly refers to individuals that for various reasons developed combinations between the two sexes, or are otherwise ambiguous. The scale analogy is not very good because even intersex conditions occur in recognizable categories rather than gradual scales (i.e. Turner Syndrome, XYY Syndrome, etc.).

When two elements join chemically it is considered a compound, not a new element. In the same way, intersex does not seem like a distinct sex but the presence, in one individual, of both male and female sex features. Nevertheless, I can understand how an intersex person might desire a third catagory of sex rather than be defined by one's diagnosis.