I read a book about a parallel world. I remember a young, humanoid man who lived in a world where no one showed any warmth to anyone else, life was extremely cutthroat, and meanness was universally admired. The only exception to this was women looking after their young children. That said, I remember a scene in the book where a mother is reluctantly abandoning her son, who has aged out.
Our hero (I can't remember anything about him) manages to travel to this world, and I remember there was some question as to whether or not the atmosphere would be breathable for him.
Sorry, I can't remember much more, but if anyone can point me in the right direction, I'd be very grateful!