Essay:Polygyny

Postcard, c. 1910

Polygyny is the marriage, or other form of mating, between one male and multiple females. Like polyandry and polygynandry, it is a form of polygamy. Biologically, polygyny is defined as "a mating system in which sexual selection acts more strongly on males than on females." Polygyny tends to occur in species in which the minimum parental effort of the female needed to produce an offspring is greater than that of the male. Anthropological and archeological evidence shows conclusively that humans have been mildly polygynous throughout evolutionary history. This has also been confirmed by molecular genetic data showing that until recently only a few men may have contributed a large fraction of the Y-chromosome pool at every generation. Serial polygyny occurs when a man marries, divorces, and remarries. A 2010 Columbia Law Review article estimated that 30,000 to 100,000 Americans practice plural marriage. It is somewhat frowned upon, though; the DSM-IV-TR says, of people with antisocial personality disorder (also known as psychopathy or sociopathy), "They may have a history of many sexual partners and may never have sustained a monogamous relationship."

Sociobiological aspects

In polygynous species, males tend to be larger than females; more males than females tend to be conceived and born; males tend to die younger as a result of physiological malfunction than females; males tend to engage in more risky activities in the context of acquiring mates than females; males tend to have higher mortality than females as a result of external causes, such as combat, disease, and accidents; males tend to exhibit more general aggression than females; more often than females, males tend to engage in escalating violent aggression that leads to injury and even death; pre-adult males tend to engage in more competitive and aggressive play than pre-adult females; and males tend to be less discriminating about and more eager to copulate with females than vice-versa.

In The Case for Discrimination, Walter Block explains that the reason for this is that in these species, females are relatively precious while males are relatively expendable or extraneous since "one man could fertilize hundreds of women". Males tend to be less discriminating about their sexual partners because the resources expended by the male in producing offspring are much less than for the female. As Ludwig von Mises writes, "Satisfaction brings him relaxation and mental peace. But for the woman the burden of motherhood begins here." While the male's physical contribution may be limited only to the amount of materials and energy needed to produce an ejaculate and place it into the female's vagina, to produce an offspring requires her to expend those resources involved in several months of pregnancy and in childbirth, nursing, and so on. The male's contribution may be considered so easily and cheaply available as to approach being a free good, while the female's contribution is more of an expensive economic good. The female incurs potentially greater opportunity costs in producing an offspring with a particular male, because the length of the gestation period produces much greater limitations on the total number of offspring she can bear in her lifetime. The male, on the other hand, is relatively quickly biologically ready to produce offspring with another female.

The implications of this are that female parental effort is a relatively scare resource and therefore has a supply curve that is to the left of the supply curve for male parental effort. The stronger sexual selection on males impels men to strive more intensely for status and resources than women. Females tend to prefer males with status and resources, and those men who have either or both have tended throughout history to have relatively high numbers of offspring as a result of having both more mates and having more mates of high reproductive capacity. In women, such capacity is strongly related to youth, which in turn is strongly linked to female attractiveness, a highly sought-after trait in the mate market.

There are two main models of conditions for the evolution of polygyny, both of which assume a social system based on female mate choice and a situation in which a female is better off if she mates with an already mated male. The competitive female choice model assumes that the females of a harem compete for the limited resources of the harem and thus that their fitness decreases as co-wives are added. The cooperative female choice model assumes that, within limits, a female's fitness is improved by the addition of co-wives to her mate's harem, as a result of cooperative interactions within the group. It appears that in families in which men are the sole breadwinners, the competitive model would be more likely to apply, while in families in which some of the women also earn money, the cooperative model might be more applicable. Most modern polygynous families operate in the latter manner out of economic necessity.

William L. Anderson refers to fractional reserve banking as a bank's committing "a form of polygamy with the money of its depositors" in that each dollar deposited is associated with more than one dollar lent.

Economics

Mises viewed polygyny as a practice that prevailed where the principle of violence dominated: "A more powerful lord has the right to dispose also of the wives of his subjects." He viewed polygyny as arising from a situation in which women are a form of property: "he demands fidelity from his wife; he alone may dispose of her labour and her body, himself remaining free of any ties whatever." In some societies, polgyny has been mandatory, often with a religious justification. After Anabaptist Dutchman Jan Bockelson drove the Catholic and Lutheran men out of Münster, the city had three times as many marriageable women as men. By August 1554, Bockelson had coercively established compulsory polygamy; he amassed a harem of 15 wives and the "rest of the male population also began to take enthusiastically to the new decree". Compulsory marriage was ordered for every woman under a certain age. The Turgot Collection describes polygyny as, in the empires, "a practice which was as common as the limits of individual fortunes allowed." Pope Gregory I opposed polgyny, which along with other prohibitions enabled the church to obtain wealth by reducing the number of families with heirs. Lacking heirs, they would most likely bequeath their property to the church.

David Friedman points out in Hidden Order that when men are allowed to have more than one wife as long as all parties consent, the demand curve for wives shifts out, causing the price to go up, thereby benefiting women. Mises Institute leaders have supported polygamy legalization, with Lew Rockwell stating that "if we believe in freedom, people should be able to do this" and Doug French arguing that recognition of plural marriages would reduce welfare fraud and otherwise allow the rule of law and rule of economics to control polygamy's abuses. Wendy Kaminer points out that even if it is the case that polygyny encourages child abuse, this still would not justify categorical prohibitions on polygyny, any more than alcohol's use to facilitate date rape would justify banning alcohol.

Polygyny has been described as being like capitalism, in that both are "systems designed to reward the winners and punish the losers; socialism and monogamy are systems designed to reward the losers and punish the winners." Like other forms of egalitarian interventionism, compulsory monogamy can be considered a revolt against nature. It defeats or ignores an evolutionary mechanism for improving the fitness of the species by using males as what Block refers to as a "crap shoot" in which "some men get very, very good genes, and other men get very bad genes and end up in a bad way." This manifests itself, for instance in the fact that men are much more likely than women to be institutionalized in prisons and mental hospitals and to die relatively young, but they are also much more likely to become CEOs of companies, chess grandmasters, Nobel Prize winners, and so on. The standard deviation of men's abilities, intelligence, and so on is greater than that of women; more women than men are clustered toward the center of the bell curve, while men are more likely than women to be represented at the top and bottom tails of the bell curve.

Polygyny allows men to "win big in a way that no woman could ever win, and lose utterly in a way that very few women do." The outcome is that excellent genes rapidly get propagated widely through those successful men mating with many women, while poor genes get weeded out through those unsuccessful men not having any women to mate with. Enforced monogamy makes it more likely that some women will have to either go single or mate with the least desirable men, since the more desirable men are already taken.

The characteristics that disable men from being able to mate or that enable a man to mate with multiple women need not always be entirely wealth-related. In some cases, a man who is able to succeed at least moderately in the work world is also so socially awkward as to be unable to attract a woman, rendering him sterile by dictionary definition ("not able to produce children or young"). On the other hand, a man might be able to mate with multiple women by being exceptionally socially skilled, putting more effort into seeking after women, and so on. One might regard it as similar to marketing a product, in that it depends on having certain talents, putting forth effort, being willing to risk rejection, and so on.

As with other economic phenomena, in order to analyze the economics of polygyny, it will be helpful to use the objective exchange value of commodities as a unit of calculation. For example, if a woman (as demonstrated by her mate choice) would equally value (1) a man who provides $250K in wealth but is unwilling or unable to perform households repairs, cook dinner, and buy flowers on her anniversary and (2) a man who offers $225K in wealth but is willing and able to do all those things, then it would be logical to conclude that those services are worth $25K to her. For convenience, the examples presented in this article reduce the value of all such services to their monetary value. As with money, his labor is an economic resource, the sharing of which with one wife potentially reduces the amount available to the others (except, in some cases, when there is a great deal of unused capacity going to waste), although there may be economies of scale.

Sharing

Certain attributes of a man, such as physical attractiveness, are not necessarily greatly diminished by being enjoyed by more than one woman. Three prominent theories are that women prefer physically attractive mates because attractive features connote genes that will contribute to the production of offspring with increased survival; because choosing such mates gives their children, especially their sons, genes that will make them sexually attractive and thereby likely to have more and better partners and produce more children (the "sexy son" hypothesis); or because more physically attractive mates provide their mates and offspring with more material benefits (food, protection, freedom from contagion, etc.) A man's assistance of one woman in producing an attractive child does not greatly diminish his ability to assist another, since his reproductive resources are difficult to exhaust through usage.

As Mises notes, "Only one person can have a given quantity of grain, but several may have a hammer successively; a river may drive more than one water wheel." Both the hammer and the river are limited resources; the hammer can only be used by one person at a time, and will eventually wear out; likewise, there is only a finite amount of space along the river bank on which to place water wheels. But the hammer may be needed by each person so infrequently, and wear out so slowly; and there may be so much room along the river bank, that these resources seem almost unlimited, for practical purposes. The sharing of a man's wealth with his wife is similar to the sharing of grain, while his sharing of reproductive resources is more similar to the sharing of the hammer or the river. In making economic calculations, if for example two women would equally value (1) a man who offers each $200K share of his wealth, and (2) a more attractive man who offers each an $150K share of his wealth, it would be reasonable to conclude that the use of his greater attractiveness is worth $50K to each woman. If a sufficiently difficult-to-exhaust resources were valued highly enough by women, it could be possible for a man to thereby mate with many women without the need to share much monetary wealth with them; and in fact, this has been observed to occur rather frequently in the mate market, for example, with some men who are considered fun, charming, good-looking, skilled in certain respects, etc.

Sharing is sometimes, but not always, more efficient than monopolizing use of a resource. An office photocopier, for example, may be so expensive that it is worth sharing it among employees, even if they have to walk down the hall to get to it and occasionally wait for a lengthy print job to complete. It would be a waste of resources to give each employee a dedicated photocopier that would mostly remain idle. A hammer, on the other hand, may be conveniently shared among family members, but it would often not be worthwhile to share it among neighbors. Hammers are so readily available at low cost that it is not worth the trouble of having to wait for a neighbor to finish using it, or to walk across the neighborhood and engage in the social interaction needed to request the use of it.

Likewise, it could be more efficient for many wives to share a husband with rare, highly-valued, shareable characteristics, depending on factors such as their geographical closeness, ability to get along, tolerance for his occasional unavailability due to being occupied with another wife, etc. Typically a scheduled rotation of the man's availability to each wife is practiced. Exceptions to the rotation may be made to the schedule for birthdays and anniversaries, when a wife is ovulating and trying to get pregnant, or when the husband needs to be with a wife to deal with problems that need immediate attention. Other aspects of family life may follow the rotation schedule as well, such as the seats wives occupy in the car. According to sociologist Janet Bennion, successful polygamist families deal with challenges by putting the scheduling and budgeting into the hands of the wives. In most plural marriages in modern countries, there is a combine dyadic and communal budget system in which to some extent a husband and each wife function independently of other husband-wife couples in the family, while some resources are pooled and some money is assigned and spent collectively.

Another problem that occurs with shared resources is that sometimes people do not leave them in as good a condition as they found them, to the detriment of the other users. For example, in a polygynous marriage, if one wife contracts a venereal disease and spreads it to the husband, it could then spread to the other wives. A counter-argument is that polygyny actually helps prevent the spread of such diseases by providing the man with additional long-term partners whose sexual availability reduces his desire for extramarital affairs.

The presence of other wives could sometimes be advantageous to the women. It could provide an opportunity to prospective wives to scrutinize how the husband behaves toward his other wives. The fact that if he becomes attracted to another woman, he need not necessarily divorce his first wife to be with her, could improve the ability of the first marriage to survive, while also allowing the second woman to become a wife rather than mistress. In some cases, the wives could regard themselves as a sisterhood or circle of friends, or even as wives not only of the husband but of one another, providing companionship and emotional and other forms of support, rather than being rivals. In some cases, the wives are already friends before they enter into the plural marriage.

The children can be looked at as children in common, and the union can be regarded as joining the family rather than sharing a man. In many ways, the plural marriage provides a backup plan in case something does not go as planned. For example, if one wife cannot have children, she can still raise the others'; if something happens to the husband, there need not be a widow who finds herself alone, because the wives can stay together. Likewise, during nights when the husband sleeps with one of the wives, the others need not sleep alone; they can sleep with the children.

Some of the wives may be employed, thereby providing more income sources to the family. Spouses could take turns babysitting the children, so that the children would not be required to spend as much time without an accompanying parent, and the parents would have more freedom to go places from time to time without bringing the children. Both the husband and one or more of his wives are free to earn an income outside the house without hiring a babysitter, as long as one wife is at home to take care of the children. It is common for the children to think of all the women as their mothers. A common arrangement is to compromise between privacy and communality by having separate apartments for each wife in the same house. In such arrangements, the children may benefit from having more siblings to play with.

Polygyny might effect some changes in the balance of power in the household. The great influence that some wives in monogamous marriages have over their husbands could in some cases be partly because he has no other providers of wifely services, perhaps because he overpaid for the first one. If, with the wealth and other resources he had available to invest in wives, he could have polygynously married two other women equally as satisfactory as her, but instead expended all of those resources on her, then he may be too poor at the moment to immediately switch to another woman, and she can behave, at least to some degree, as a monopolist. In a monogamous relationship, there may also be greater switching costs in time and effort involved in finding another equally satisfactory mate, if the first one leaves or stops providing services. Therefore, the most expedient response to a dispute in many cases might be for him to acquiesce.

As Mises warns, "if the tailor goes to war against the baker, he must henceforth produce his bread for himself. If he neglects to do this, he will be in distress sooner than his adversary, the baker. For the baker can wait longer for a new suit than the tailor can for fresh bread." As has been observed since ancient times, in marital disputes, a monogamously-married husband may find himself in the position of the tailor — i.e. sooner in a state of distress from the interruption of relations than his adversary.

In polygyny, on the other hand, another wife may be readily available to provide what one wife refuses to. There may even be interwife competition in some cases; as one polgynist is quoted as saying, "There is nothing better than having two wives trying to outdo one another, which means that the man stands to gain a lot." However, that might not be the case if the wives band together to collectively attempt to curb what they view as misbehavior on the husband's part. On the other hand, as Rothbard notes, "a cartel is an inherently unstable form of operation" since one or more members may find it in their interests to disobey production restrictions. Then again, Rothbard's analysis applies mainly to producers of homogenous commodities, each of which producers is capable of increasing its production to make up for what the other cartel members refuse to provide. Women and their services are not homogenous and their productive (or reproductive) capacities are limited.

Winners and losers

Highly desirable women and the majority of men tend to benefit from monogamy, while highly desirable men and the majority of women tend to benefit from polygyny. The following example illustrates why. Suppose there is a population consisting of five men (Andrew, Ben, Cecil, Dan, and Edmund, in descending order of wealth) and five women (Francine, Gertrude, Helen, Isabel, and Judy, in descending order of desirability). Under monogamy, assuming the use of an efficiently-operating mate market with perfect information and that men choose women based on desirability and women choose men based on wealth, they will be paired up as follows:

Monogamy mandated

Man		Woman
Name	Wealth	Name	Desirability	Share of husband's wealth
Andrew	$850K	Francine	Most desirable	$850K
Ben	$410K	Gertrude	Second most desirable	$410K
Cecil	$300K	Helen	Third most desirable	$300K
Dan	$250K	Isabel	Fourth most desirable	$250K
Edmund	$100K	Judy	Fifth most desirable	$100K

Now suppose that polygyny is used instead. Given the assumptions mentioned above as to the actors' preferences, and also assuming that men prioritize quality of mates over quantity of mates, they will now be matched up as follows:

Polygyny permitted

Man		Woman
Name	Wealth	Name	Desirability	Share of husband's wealth
Andrew	$850K	Francine	Most desirable	$425K
		Gertrude	Second most desirable	$425K
Ben	$410K	Helen	Third most desirable	$410K
Cecil	$300K	Isabel	Fourth most desirable	$300K
Dan	$250K	Judy	Fifth most desirable	$250K
Edmund	$100K	Single

Here, all of the women have acquired more wealth except for Francine, the most desirable woman, who lost wealth. All of the men have ended up with either less desirable women or no woman at all, except for Andrew, who gained a woman (and the second most desirable woman, at that). The social effect of this is that more children will tend to be born into wealthier homes. The facts that Andrew's wives are highly desirable, and that desirability in women typically involves attractiveness, and that youth is a major factor in female attractiveness, and that young women tend to be more fertile, means that Andrew has two wives with many years of high fertility remaining ahead of them. He is therefore in a position to father a large number of children if he wishes. The other men have women of lower desirability, which could very well mean they are not as attractive, youthful or fertile, and will tend to produce fewer children.

Not only will Andrew have more children, but his offspring will tend to be relatively genetically diverse due to the two mothers contributing different sets of genes. This provides more opportunities for combinations of genes to result that will be closer to optimal for the environment the children will encounter, and provides insurance in case one of the mothers should happen to have problematic genes or fertility issues. At the other extreme is Edmund, who is not in a position to father any children.

When laborers are added to any economy, the potential for improving efficiency through division of labor increases: "Exercise and practice of specific tasks adjust individuals better to the requirements of their performance; men develop some of their inborn faculties and stunt the development of others. Vocational types emerge, people become specialists. The division of labor splits the various processes of production into minute tasks, many of which can be performed by mechanical devices." In a polygamous family, one parent might specialize in home-schooling; another might earn money; another might do housework. There may be economies of scale; for example, the effort and time involved in shopping and cooking for 24 children is probably not twice that required when there are only 12. Hence the Frank Bunker Gilbreth, Jr. and Ernestine Gilbreth Carey book, Cheaper by the Dozen. Feminist Vicky Burgess-Olson notes that many women found polygyny liberating because the availability of other wives to take care of domestic tasks provided opportunities to earn degrees and pursue careers:

91 percent of the wives I studied gave consent for the second and further marriages. Often it was the woman who suggested, "Maybe we'd better take another wife," and sometimes the first wife gave the subsequent bride away at the wedding. . . . If the families shared the same house, the women had different assignments and could usually do what they liked best. Not being stuck with so much of the housework freed them for things like going to concerts or church. Of the sister wives I studied, 54 percent had full-time jobs outside the home. . . . [w]omen became poets, lawyers, businesswomen, newspaper publishers.

On the other hand, there may also be the same sort of diseconomies of scale that companies experience as they grow, such as communication costs, duplication of effort, and "office politics" (or in this case, household politics). Reaching decisions by consensus is easier when there are fewer participants. If several spouses are shopping, then they may have to set up more elaborate methods of familial communication and coordination in order to not inadvertently duplicate one another's effort by buying the same products, than would be required when there are only two spouses. In some cases, a family member might make decisions for personal gain that are not in the best interest of the family, and get away with it by currying favor with the right people. For example, a wife might get lazy about chores, knowing that her husband enjoys her in other ways so much that he won't hold her accountable for other neglected household tasks. This could be especially problematic if the there are inadequate contractual protections of each participant's rights and there are barriers to exit, such as a desire to keep the family together for the sake of the children. In an autocratic household, the husband might pursue his own self-interest at the expense of one or more wives, and in a democratic household, the majority might pursue its own interests at the expense of the minority. The problems usually associated with organizations that it is difficult or costly for participants to withdraw themselves and their investments from could apply.

Having multiple spouses, each with different want-satisfying characteristics, can have some of the same advantages as, say, having more than one kind of berry on hand. Not all goods are fully convertible goods. A consumer may have a variety of desires but find that one product, by its nature, cannot be adapted to gratify them all. In the case of labor, one person might not be willing or able to provide all the different kinds of services that one could want performed; in the case of foods, one type of food is not designed to stimulate one's taste buds in every possible way one might want them to be stimulated.

A strawberry, for example, cannot also taste like a blueberry, or at any rate trying to flavor it to taste more like a blueberry would not be worth the effort; it would be more practical to just buy both strawberries and blueberries so as to satisfy whatever sort of craving may arise. Having both available not only makes it possible to satisfy those two incompatible yearnings, but also allows for the creation of new flavor possibilities by combining them, for example into a strawberry-blueberry smoothie, which simultaneously provides two different kinds of pleasure. This may be superior to either flavor by itself, as evidenced by the popularity of such mixtures at smoothie bars. As one adds more types of fruit to one's refrigerator, the number of possible combinations increases exponentially, and is limited only by imagination, palate and the constraints of the physical universe. The implications of this principle to polygamy are obvious.

The following example illustrates. Just as in aforementioned example of berries, it is possible to make them into sundaes, or smoothies, or fruit salads, and so on, spousal enjoyment methods can include all known options for receiving pleasure from spouses, such as conversation, going on vacations together, etc. As new enjoyment methods are added, the number of possible combinations increases according to a parabolic formula, but as spouses are added, the number of possible combinations (e.g. going on a cruise with Francine and Gertrude or picnicking just with Helen) increases exponentially.

Of course, increasing the number of spouses involved in various activities may not result in a proportionate increase in satisfaction, due to the laws of diminishing marginal utility and diminishing marginal returns. This table assumes that all want-satisfiers are compatible with all enjoyment methods; that different want-satisfiers are compatible with one another; and that different enjoyment methods are incompatible with one another. If all enjoyment methods were compatible with one another, then the formula would use an exponent of an exponent, and thus the number of possible combinations would increase much faster as more of either or both limiting factors were added.

Number of want-satisfiers	Number of enjoyment methods	Combinations possible	Formula
1	1	1	(1 + 1)1 - 1
1	2	2	(2 + 1)1 - 1
1	3	3	(3 + 1)1 - 1
2	1	3	(1 + 1)2 - 1
2	2	8	(2 + 1)2 - 1
2	3	15	(3 + 1)2 - 1
3	1	7	(1 + 1)3 - 1
3	2	26	(2 + 1)3 - 1
3	3	63	(3 + 1)3 - 1

Dan Savage argues, "I acknowledge the advantages of monogamy when it comes to sexual safety, infections, emotional safety, paternity assurances. But people in monogamous relationships have to be willing to meet me a quarter of the way and acknowledge the drawbacks of monogamy around boredom, despair, lack of variety, sexual death and being taken for granted.”

Social benefits

Polygyny could help to break the cycle of poverty, in which children are born into poor homes, perhaps receive the same kind of poor genes and poor upbringing that caused their parents to be poor, and do not have the advantages of the better education that wealthier families can afford. Monogamy results in unions like those between Edmund and Judy above — that is, between the poorest men and the least desirable women. Polygyny might be a superior method of maximizing the satisfaction resulting from the allocation of the limited childbearing and childrearing resources available to society. The progeny of all of the women in this example (except Francine, whose portion is diluted by having to share with Gertrude) benefit from being born into a wealthier household.

Polygyny also opens up a new realm of competition among men. Andrew may, for instance, notice that if he increases his wealth from $850K to $1231K (a little more than triple the $410K that Ben has, he will be in a position to bid Helen away from Ben and thereby acquire a third wife (and the third most attractive, at that). One reason many men already feel impelled to try to earn more money is so that they can be choosier when looking for a spouse. The possibility of acquiring not only better but more wives could provide an additional incentive for men to increase their productivity. Notice that under monogamy, at soon as Andrew's wealth exceeds Ben's ($410K), he already has acquired the most desirable wife available. Under polygyny, he has an incentive to acquire as much as $2,051K (a little more than quintuple the $410 that Ben has) because that would allow him to bid all five wives away from the other men. Therefore, there is a potential for polygyny to spur economic productivity. Since other qualities valued by women can at least partially compensate for a shortfall in money, polygyny could also heighten competition among males to improve themselves in other ways (e.g. becoming more physically fit, being more attentive, etc.)

In particular, men in Edmund's situation will have a great incentive to try to acquire more wealth (or learn to better provide other services that women will value), because it is now not just a matter of how desirable a woman he will be able to attract, but whether he will be able to attract any woman at all. As Henry Hazlitt points out, "a man will put forth greater efforts to save himself from ruin than he will merely to improve his position." On the other hand, as French observes, under polygyny "there will be a few men (and women) with multiple spouses, but not many. The fact of the matter is most people don't offer enough value for potential spouses to consider sharing." As the table above illustrates, a relatively small wealth inequality does not always, ceteris paribus, enable a man to attract a second wife. In some cases, as in Andrew's, he has to have twice as much wealth as his competitor.

The availability of polygyny as an option could encourage the making of long-term commitments by creating another option that some people might find more satisfactory than monogamy. If monogamy is the only option, some men might deem marriage to not be a good enough deal to be worth the costs (including opportunity costs); it might be more advantageous to forgo the woman who demands marriage in order to continue to play the field. Polygyny offers a compromise between a committed monogamous relationship and no long-term commitment at all.

Even if the state refuses to officially condone polygyny and to issue marriage certificates for multiple spouses, it might still be possible under contract law to accomplish most of, all of, or even more than, what people seek to achieve by the type of marriage the state offers — that is, a binding agreement that provides some security in the form of required financial support or other remedies if the other party breaches the agreement. Questions such as what each spouse is expected to provide to the family, whose consent is necessary to add new spouses to the family, and so on can be settled by contractual provisions. The only downside is the fact that current tax law and the employer health insurance plans that the government encouraged to exist often discriminate in favor of those who have obtained state marriage certificates.

Differences from polyandry and group marriage

Polyandry could also occur under certain circumstances. Similar economics would apply. If a woman's want-satisfying power greatly exceeded that of her competitors, she might be able to attract more than one man, by offering each more satisfaction than he could obtain from a lesser woman devoted entirely to him. Polyandry would require that one or both of the men be willing to accept receiving less than a full allocation of her childbearing resources. The restriction of one party's ability to reproduce due to competition from another spouse tends not an issue in polygyny, because the biological contribution of the male to the offspring requires so little resources out of what is available that the husband can easily impregnate all of the wives as many times as they desire and are able to be impregnated.

As mentioned, the polygynous nature of the human species has resulted in men tending to have stronger sexual desires than women. In a monogamous situation, this can result in one party or the other, or both, having to make concessions — e.g. the husband receiving less sex than he wants or the wife more sex than she wants. Polygyny can make it easier to achieve a sexual balance in the household in which two or more women contribute toward satisfying the husband's sexual desires, thereby requiring less effort from each of the wives to achieve the same level, or greater, of satisfaction on his part. In contrast, polyandrously-married women tend to find the responsibility of fulfilling multiple husbands' sexual expectations onerous.

Many different configurations, such as two women and two men, are possible. These are known as polygynandry. It is largely a matter of personal taste and preference, and of offering each desired participant what is needed to impel him to participate, so long as the cost is not deemed so great as to not be worth it. There are a variety of reproductive strategies that different people and groups of people are willing to pursue and that are best suited for them, and not everyone is even focused on or interested in reproduction; some form relationships for entirely unrelated reasons.