Masculinity and femininity are hard to pin down descriptively in part because the markers we associate with each change over time and from place to place. So what that leaves us with, I think, is identification and desire to belong to one or another or neither or both. As for what each should be, I would say that the ideal beyond style and manner is to be a good person to yourself, to others, to your community, and the world as a whole, while maintaining your identification.