When shapeshifters or body hoppers get a bit funky with gender/sexuality
Bonus example from the comments: "Luke (My High School Friend Became a Succubus): Various humans on Earth transform into Demihumans with matching forms. Luke became a Succubus which due to them being a female only species meant he also became biologically female.
He's unsure what exactly that means for his gender or sexuality."
u/GoddessOfSuccubi — 7 hours ago