If Anet ever decides to have it where player characters can be paired with an npc depending on the gender of the character. And Anet dose not limit, who the player character can be paired with.
Well personally I'm gonna have my male human character Eidon Abramm in guild wars 2 fall in love with a female charr. Course there have to be a reaosn for this to be able happen in game, and its very unlikely this well ever happen. (I just love female charr their all cute to me.)