Can you tell me the name of this book? Involves Utopia.?

Hello!!! In 8th grade my teacher made us read this book that involved Utopia. The story follows the main character, a boy, as he receives his first job in society. He begins to question the ways of a society and when a child is born who must be killed for being different (i think it was because his eyes were a different color) the main character kidnaps him and they leave the society. In the end they freeze to death all alone.