There is, of course, profound disagreement today about what marriage actually is. The center of debate concerns how marriage is related to procreation and the rearing of children. Is marriage intrinsically related to having and rearing children, or is this only one of the benefits – or burdens – attached to some marriages, but only incidentally? In turn, this issue raises other questions: Is marriage only an emotional-spiritual relationship (or a union of hearts and minds), or instead, does it essentially include bodily union, sexual intercourse being a constituent part? Is marriage necessarily between a man and a woman, or can there be genuine same-sex marriages? Is marriage necessarily a union of two people, or can there be genuine marriages of three or more persons (triads, quadrads, etc.) in polyamorous sexual partnerships? Does marriage even have an objective structure, or instead, are its basic contours subject to the choice of the state or to the choices of individual couples? All of these questions concern what marriage is. Two further questions bear on attributes or properties of marriage (logical consequences of what marriage is): Is marriage inherently an exclusive bond, or may marriages be sexually “open”? Does marriage necessarily involve a sincere pledge of permanence, or may marriages be for set terms or “for as long as love lasts”?