" Hearth-brothers, or friends,” he said, and saying it was remote, out of reach, two feet from me in a tent eight feet across. No answer to that. What is more arrogant than honesty? Cooled, I climbed into my fur bag. “Good night, Ai,” said the alien, and the other alien said, “Good night, Harth.” A friend. What is a friend, in a world where any friend may be a lover at a new phase of the moon? Not I, locked in my virility: no friend to Therem Harth, or any other of his race. Neither man nor woman, neither and both, cyclic, lunar, metamorphosing under the hand’s touch, changelings in the human cradle, they were no flesh of mine, no friends; no love between us. "
― Ursula K. Le Guin , The Left Hand of Darkness (Hainish Cycle, #4)