If you were the last person in the world.

I just finished reading Z for Zachariah by Robert C. O'Brien. It's a post-apocalyptic novel about a 16 year old girl and a 30 year old man who are the only known survivors of a nuclear war.

They meet each other after a year, and about halfway through, the book gets all creepy because the man tries to rape her. The story moves from man vs. nature to man vs. man.

I thought that was such an odd thing for a character in that situation to do. I think if the last two people in the world are roughly reproductive age, they're naturally just going to have sex eventually anyway.

It's human nature. Look at Adam and Eve. They obviously figured out what needed to happen. Even if they don't like each other much, what other choice did they have?

Then again the book wouldn't be as exciting if the characters just naturally had sex.