It would seem that to do a compare-and-contrast essay on Hemingway's story "Hills Like White Elephants" you would be almost forced to compare and contrast the two main characters with respect to how they feel about the girl being pregnant. The "contrast" part would be fairly simple. She wants to have the baby and the man called the American doesn't want her to have it. You might explain why she wants a baby and he doesn't. She wants it because it is instinctive with her, as it is with most women. It is against her instincts to abort a baby. He doesn't want it because it will tie him down. As far as the "compare" part, you could tell about the things they have in common. They love each other. They are both bright, sophisticated people. They enjoy traveling and "trying new things." They have fun together. The baby, of course, is a result of their love, but it is tearing them apart. You might speculate about whether these two are married. My opinion is that they are. Otherwise I doubt that the girl would want to have the baby. It was unthinkable in the 1920s. Yet she never says anything about wanting to get married. At one point she says:
"Doesn't it mean anything to you? We could get along."
So I assume they are already legally married. The author's objective style creates some confusion. Hemingway avoids exposition and forces the reader to make guesses based on what the reader can "see" and "hear."