Using family as an operational surrogate in a statutory plan aimed at assuring the stability of a neighborhood is overbroad because it thereby rules out many legitimate associations that would not introduce neighborhood instability. Additionally,family is underinclusive in that it allows many arrangements that would undermine neighborhood stability. Our desire is to understand how the world came to be the way it is-why prejudices and conventions assumed the forms that they did rather than some other form. Readers will judge for themselves, and will differ, whether what is and has been is also what should be. Because our province is positive theory, we do not insist that the rational preference for traditional families necessarily leads to the conclusion that such families are axiologically superior forms of domestic organization. However, without accepting the preference for traditional families as rational rather than accidental, capricious, or “merely religious,” any normative case for alternative arrangements is unlikely to be convincing.