There is no reason, outside of religion, that the size of a family must be fixed at 2 adults + zero or more children. And since the first amendment of the constitution puts protection the sanctity of anything completely outside the purvue of the federal government, sanctity being a purely religious concept, the laws that limit families to that size are completely unconstitutional. (Yeah, I know, the constitution also forbids the existence of the FDA, the DEA, two thirds of the ATF, the various educational prevention organizations, and most of the rest of the federal government. But none the less ... ) So why not allow families to be formed by any group of consenting adults that chooses to form one?
Some will surely say that human biology precludes this arrangement. Humans, they will say, have a biological imperitive that forces them into monogamous relationships. (Obviously, they never met my ex). They will be completely wrong, but they will say it none the less. To mis-quote Robert A. Heinlien, forgive them: for they are young and think that the customs of their tribe are laws of nature. Not only is there no such biological imperitive, but globally, plural marriage is allowed in the cultures of something like one third of the world's population, including Muslim countries, among the Bedouin of Isreal, among Jews in Yeman, among traditional Mormons, in several experimental Christian groups, and many other societies.
Morover, many of the societies that do not practice plural marriage, including mainstream Jews and Mormons, do not practice it because they have been forced or intimidated into giving it up ... Our government flew in the face of it's own constitution by forcing the Mormons to abandon the practice as the price of statehood for Utah, and I am told that some Jewish sects gave it up for fear of angering the Gentiles.
In many of the societies that do practice plural marriage, economics limits the practice to about 10% to 25% of the population. This, in my opinion, is due to two major factors: in many of these societies the economic status of women is limited, and their ability to work, is savagely curtailed. And often only poligamy ... one man, more than one women ... is practiced. But there is no reason this must be the case!
Imagine the opportunities availiable with plural marriage. A family of eight adults with 16 children could afford to allocate two or more full-time caregivers to the children, and still field up to 6 breadwinners! Two cannot live as cheaply as one, and 24 cannot live as cheaply as 16. But 24 can live together much more cheaply than they can live apart. Even with our corpulent government, this should be enough to allow economic success, and discretionary income as well. This discretionary income could be used to finance continuing education or to invest in starting a business, further increasing the economic opportunities of the family, and decreasing our dependance on corporations to create jobs. The possibilities are endless. No longer would men or women be unable to enjoy child-rearing due to medical problems. No longer would economies of scale be availiable only to business. A large clan could provide it's own group health coverage, or simply marry a couple of doctors!
People will wonder: how will we handle the legal implications of such groups? What about divorce, alimony, separation, health benifits from employment, and other issues? That's the easiest part. Rather than the one size fails all scheme of marriage we have today, entering into a plural family would simply be a matter of executing a contract. Most of these issues, like inheritance, divorce and alimony would be specified in the terms of that contract. No-one would be able to say 'the terms of this contract are unfair', since they would have negotiated those terms themselves in the process of forming the union. As for health benifits and insurance, those issues would be (slightly) more complex, as they involve third parties. But companies like to make money, and if there is demand for a service, it will be provided. The only reason that companies sometimes balk at providing services to 'domestic partnerships' is that they are sometimes required by law provide services at a loss. This, too, would become a non-issue in the presence of freedom.
Of course the ruling parties won't like these ideas.
The Democrats will fear that these arrangements could erode the victim class that has become their base. And they would be right. Only government needs a victim class, and only over-regulation and violence can create one. The victim class would become a thing of the past, as people freely formed the alliances that made sense in their own lives, and met their needs.
Republicans, on the other hand, will panic when they consider the sexual implications: Who, they will wonder, would sleep with whom in the presence of such freedom? How will we impose Christian morality on these people? Well, Mr. Bush, the imposition of Christian morality -- or that of any other religion -- by the government is unconstitutional. I know that means little to you, but it is still important to some of us. But to answer your question: I don't know who sleeps with whom -- and I'm not asking.