What is a family, and what distinguishes it from other kinds of associations? Is the traditional role of the family merely grounded in custom and habit, or is there a deeper philosophical justification for it? How has the structure of families changed over the ages, and how does it differ across cultures? John and Ken examine the structure and function of the family in relation to morality, values, and evolution with Stanford sociologist Michael Rosenfeld, author of The Age of Independence: Interracial Unions, Same-Sex Unions and the Changing American Family.