Call to family, community, and participation is the second key theme of Catholic Social Teaching. Immediately after forming Adam God said: "It is not good for the man to be alone.". The Church teaches that man is now not only a sacred but also a social animal and that families are the first and most basic units of a society. Full human development takes place in relationship with others. The family—based on marriage between a man and a woman—is the first and fundamental unit of society and is a sanctuary for the creation and nurturing of children. Together families form communities, communities a state and together all across the world each human is part of the human family. How these communities organize themselves politically, economically and socially is thus of the highest importance.