As a female MC straight potions make the orientation "homosexual", while gay potions make "heterosexual". Is this an issue with the orientation text or the potions?
If I had to guess as a programmer myself: since the game is based mainly around male/male content, take the potions change your character to "Only into guys" or "only into girls". That means homosexual actually means "only into guys" in terms of the game's code itself.