That's not really the reason people avoid using "it" as a pronoun. The reason is that it sounds dehumanising, as if referring to the person as an object. I do actually have a context example: in Wuthering Heights, Heathcliff consistently refers to his son as "it", even though he knows Linton is a boy. It's nothing to do with gender at all here; the point is to show how little he cares about his son as a person, and that he considers him a tool. Or, as a more GW-specific example: the Weapons Test Engineer: "It keens with outrage, the vermin! As if that will save it!" He can clearly see Braham is male. He's using "it" because it dehumanises the test subjects, just like calling Braham "vermin".