The Eldraeverse

Everyone Is Bi: Or at least can be, thanks to advances in sophotechnology making gender identity and sexual orientation as editable as any other mental properties, and reinstantiation in general making actual sex changes not all that much more complicated than flipping a few switches in the preferences screen of your brain.  And are, in fact, not merely readily changeable, but entirely optional.  But yes, most people have explored at least some of the implied possibilities.