Surely cannibalism is justifiable, if 3 humans are left of an otherwise extinct race and two are men and one is a woman. If there was no food around (through, say, fallout) then surely it is okay to eat one of the males as the ultimate goal at this point is the preservation of our race which would then proceed that the males have to show their greatest skills which are given through hereditary and they all discuss which male is the best choice for continuing the existence of human beings.