Marriage have to be only monogamous and heterosexual?

Question: What a family is? Response, the most varied. Depending on cultural behaviours of the interlocutors is from "a production unit" up to " the fundament of society. " Obviously the family, as shown and accepted by all jurisdictions, is more than a production unit, a complex of legal title to assets, the place par excellence of the personal and emotional development of its members; is all these things together, and more of this.
But iis the dimension of "legal entity" to give the key for understanding the nature of questioning: if family is merely "summation" of the legal ownership of its founders or if we should see in a family a new and different actor in juridic world. IN western culture was the idea of family as new subject with its onw rights to impose in public arena and legislation, but from this arise some problems, the main of which are: what is meant by family? What form? Ceases to stop the will of the "founders" or maintains an independent status to some extent independently of the intention of the "constituents"?

In Western culture, sometimes also embedded Constitutions (as in Article 29 of the Italian Constitution) family is defined in Aristotelian sense as "natural society": something natural, inevitable and inescapable, a third element that, as tailed in the famous Platonic myth, leads two persons "to join" forming an entity "other", complete whilethe previous autonomous entities werent. This definition already counts some important messages: first, that "family" is not necessarily synonymous of marriage (although in many pieces of legislation the definition of family take their place alongside the corollaries "based on marriage") but is an a priori based on the need, even before the will, pf two persons that come together to improve as individuals and give meaning to their lives. Another corollary that  raises is about gender identity of those who join, which must obviously be different, not so much since the reason of a family is procreation (this idea leads Jewish and Christian culture, but ie is absent in the Indian culture from Emperor Asoka period to the Mughal dynasty, when the family goal was the spouses pleasure), but because it is only in the exchange with the "other" meant as opposite gender that people can reach an absorbing state for their individuality otherwise "mutilated".
So it is clear that in a "natural law" meaning a family can only be composed of two persons of different sex, thus excluding both polyandry and polygamy, although it (especially the second ) certainly not unknown in the West history but seen rather as a degeneration caused by the drift of the senses than arising from basic needs. But it follows also that marriage, in its sense of a contract conferring rights and mutual obligations of both economic and juridic areas, legal subjectivity, not necessarily coincide with the family as the natural a fruit of "natural order".

In fact, the marriage,  for its overwhelming contractual size, needs to be standardized, recognized, sometimes also delimited by public authority (and once religious too) and changed repeatedly role and position to the eyes of the law during historical evolution.


An example from Latin West.  14 AD an edict of Augustus forbade the freed slaves who had been married to his former master to be able to divorce without the consent of him: so for first time latin society marriage ceased to be based on freedom and equal dignity of spouses, and in few centuries, with christian ideology who became dominant from IV century, marriage will survive to spouses will and becamea sort of prison of single willness throughout all the Middle Age.

With the rise of the Protestant Reform in northern Europe, marriage become again "a thing of humans for humans" and loose its metaphisic role   reaffirming the freedom of both spouses to end it by choice and becoming again a contract. So it's possible to say that marriage purchases with the civil effects of its own constitution also the indifference to gender and number of people who want to marry, because to regulate situations as heritage the identity of the constituent is not a problem: the point for the effectivity of marriage is not in onthology but in observation ofthe rules established by the lawnmakers to validate marriage itself, a human thing regulated by laws.

So if in a natural society, a family can only be based on two persons of different sex, marriage in a "civic meaning" (that dependent on recognition of civil effects by lawmakers) becomes simply a legal, and in this sense of contract could include polygamy and polyandry, homosexual unions and any other type of relationship which whom single parlaments decide to give dignity.

So family and marriage are not synonymous and  also from a philosophical way of view is family take a sense of moral, natural and necessary structure, marriage (as legal contract) have not that and we could have some marriages that are also family in a jusnaturalistic sense and some others that have the same effect of the firsts at the eye of the law but have not the same meaning in a moral or "natural sense", but law have not to follow a single moral sense but have to regulate general situations and so can admit also poligamy polyandry and same sex unions