Back in the day (that day being 1842 ) the German doctor Richard von Krafft-Ebing wrote this famous book Psychopathia Sexualis: eine Klinisch-Forensische Studie (pub 1886)
This book discussed heterosexuality, homosexuality and something else - something the doctor used a term from botany to describe. “Bisexuality”. Bisexual flowers contain androecium and gynoecium and are called androgynous or hermaphroditic. Examples of plants with bisexual flowers include the lily, the rose and most plants with large showy flowers.
Krafft-Ebing held the view that bisexual people were mentally androgynous/intersex, that their brains contained more than one gender. Bisexuals were considered to be androgynous/intersex like Hermaphroditus, their patron demi-god/ess from Greek mythology.
And that we have our own demi-god/ess! Who is genderqueer! Bisexual smash the gender binary and monosexism. Hermaphroditus rules yo!