Why is polygamy illegal in Australia

The pros and cons of polygamy

[Article updated April 25, 2020.]

In the natural state, humans were generally polygamous, as were most animals. In many animals, the male leaves the female soon after mating and long before any offspring are born.

Genetic studies have shown that monogamy did not prevail over polygamy in the human population until a relatively short time ago, around 10,000 years ago. Monogamous unions may have developed in parallel with sedentary agriculture and helped maintain land and property within the same close kinship.

Polygamy can allow a male to produce more offspring, but monogamy can be a more successful general reproductive strategy in certain circumstances. By clinging to the same woman, a man can ensure that the woman's offspring are his and prevent those offspring from being killed by male rivals who intend to re-fertile the woman (breastfeeding is a natural contraceptive).

Historically, most cultures that allowed polygamy allowed polygyny (a man who took two or more wives) rather than polyandry (a woman who took two or more husbands).

By doing Gallic WarJulius Cæsar claimed that among the ancient British "ten and even twelve men have women in common", especially brothers or fathers and sons - which sounds more like group marriage than polyandry to me.

First, let's talk about the rarer polyandry. Polyandry is typically associated with scarcity of land and resources, such as in certain parts of the Himalayas, and is used to limit population growth. If several brothers are married to a woman (fraternal polyandry), this also protects the family's land from division.

In Europe, this has generally been achieved through the feudal rule of primogeniture ("firstborn"), still practiced in the British aristocracy, through which the eldest legitimate son inherits the entire estate (or almost) of his two parents. Primogeniture has prehistory in the Bible, especially Esau, who sold his "birthright" to his younger brother Jacob.

Today most of the countries that allow polygamy - always in the form of polygyny - are countries with a Muslim majority or a sizeable Muslim minority. In some countries like India, polygamy is only legal for Muslims. In other countries like Russia and South Africa it is illegal but not criminalized.

After Islamic marriage, a man can take in up to four women as long as he treats them all equally. Islam allows polygyny, but does not require or enforce it: marriage can only be concluded by mutual consent, and a bride can stipulate that her future husband should not have a second wife. Monogamy is by far the norm in Muslim societies as most men cannot afford to have more than one family, and many of those who prefer not to. Even so, polygyny is still widespread in much of West Africa.

Polygamy is illegal and criminalized across Europe and America, as well as China, Australia and other countries. Even so, there are many cases of polygamy in the West, particularly within immigrant communities and certain religious groups such as the Fundamentalist Church of Jesus Christ of Latter-day Saints (FLDS Church) and other Mormon fundamentalists.

What are the pros and cons of polygamy (or polygyny)? A man who takes more than one woman satisfies more of his sexual appetite, signals high social status, and generally feels better. His many children provide him with a source of work and the means to forge multiple, reliable and lasting social, economic and political alliances through arranged marriages. Polygyny may be expensive, but in the long run it can make a rich man even richer.

Even in monogamous societies, powerful men often establish long-term sexual relationships with women other than their wives (cohabitation), although in this case the junior partners and their children born to them do not enjoy the same legal protection as the “legitimate” wife and children.

Louis XIV of France, the Sun King, had a large number of official and unofficial lovers. His main mistress carried the title at all times Mistress in the titleand the most famous, Françoise-Athénaïs, Marquise de Montespan, bore him no fewer than seven children.

In some cases, a man could get divorced and marry a much younger woman (serial monogamy), thereby monopolizing the reproductive lifespan of more than one woman without suffering the social stigma of polygamy.

As I argue in my book Willy-nillyIf divorce has become so common, it is in part because people live much longer while in the past death would have done the divorce. "Until death do us part" means much more today than ever before.

Polygyny could even benefit the women concerned, who amuse each other and share the burden of household and child-rearing. Younger women can improve the status and reputation of the first woman while detaching themselves from their responsibilities. In times of war with high absenteeism and male mortality rates, polygyny supports population growth and replenishment by ensuring that every woman can find a partner.

But polygyny has its drawbacks too, of course, especially when viewed through a modern western lens.

Primarily, polygyny sanctions and perpetuates gender inequality, with wives officially and openly reporting to their husbands.

Women in polygynous unions tend to marry at a younger age, in an environment that naturally encourages jealousy, competition, and conflict, with wives poisoning each other's offspring in order to further their own.

Although in principle the husband should treat his wives equally, in practice he will almost inevitably prefer one over the other - most likely the youngest, youngest.

Tension can be relieved by establishing a clear hierarchy between the wives or when the wives are sisters (sororal polygyny) or when they each run their own household (hut polygyny).

While polygyny can benefit the men involved, it denies wives to other men, especially young men of low status who, like all men, measure their success by their masculinity, that is, by the two parameters of social status and fertility.

With little to lose or look forward to, these frustrated men are far more likely to turn to crime and violence, including sexual violence and warmongering. It is perhaps telling that polygamy is practiced in almost all of the 20 most unstable countries on the Fragile States Index.

All of this is only exacerbated by the bride price, a payment made by the groom to the bride's family. The bride price is a common characteristic of polygynous unions and is intended to compensate the bride's family for the loss of a pair of hands.

Divorce usually requires the return of the bride price, so many women have no choice but to remain in wretched or abusive marriages.

When polygynous unions are common, the resulting shortage of brides increases the bride price and increases the age at which young men can afford marriage, while encouraging families to weed out their daughters at the earliest possible opportunity, even at the expense of education interruption .

The bride price is often paid on cows, which leads some young men to resort to cattle robberies and other forms of crime. Gang leaders and warlords attract new recruits with a promise of a bride or an offer to cover her bride price.

Polygyny also tends to disadvantage the offspring. On the one hand, children in polygamous families share the genes of an alpha male and benefit from his protection, resources, influence, attitude and expertise.

On the other hand, their mothers are younger and less educated, and they receive a shared portion of the father's consideration that can be directed to his youngest wife or amassed resources for the next.

They are also at a higher risk of violence from their loved ones, especially the extended family. Overall, child mortality is significantly higher in polygynous families than in monogamous families.

So draw your own conclusions.

See my related article, Polyamory: a new way to love


Dupanloup I et al. (2003): A recent shift from polygyny to monogamy in humans is suggested by analysis of the world's Y chromosome diversity. J Mol Evol. 57 (1): 85-97.

Fragile-States Index 2017. The Fund for Peace; DHS; MICS.