I just watched the movie. I hate movies that make humans look like idiots. I know we have feelings, but main priority in this situation should be two things. Survival and future.
With one man and one woman there will be inbred. 2 guys could make you avoid this. Also more people so more people with different strengths. It doesn't make sense that inbred was not brought up. Should be THE KEY note for all in this situation. But stupid people and stupid movies. Arghhh. Irritates me!