Daniel sent us this one — and it's a big one. He's asking about the history of monogamy, what the science actually says about whether humans are naturally monogamous, and then there's a legal question that's been gnawing at me too. Religious groups that practice polygamy face increasingly hostile laws, while modern secular forms of non-monogamy fly more or less unchallenged. Is there a hypocrisy there? And what have the major religious traditions and governments actually said about this over the centuries? There's a lot to unpack here.
There really is. And I think the place to start is that opening assumption — that humans are naturally monogamous. Because if you ask most people, that's what they'd say. It's in the air we breathe. But the science tells a much messier story.
Because I've seen the pop-science version — we're somewhere between monogamous and polygamous, we're "mildly polygynous," men want to spread seed, women want security. That whole evo-psych greatest hits album.
Right, and that framing itself is part of the problem. It's not that it's entirely wrong — it's that it flattens something genuinely complex into a just-so story. So let me give you the actual biological markers. When biologists look at a species and try to determine its mating system, they look at a few things. One is sexual dimorphism — how different males and females look in body size. In species where males compete for harems, like gorillas, males are much larger. In pair-bonded species like gibbons, males and females are roughly the same size.
Humans are somewhere in between. Men are on average about fifteen percent larger than women. That's less dimorphism than gorillas or orangutans, but more than truly monogamous primates. It suggests a history of moderate male-male competition — not harem-level, but not pair-bonded purity either.
We're the slightly-larger-male primates. That's the big reveal?
That's one data point. There's another one that's even more interesting — testis size relative to body mass. In species where females mate with multiple males in quick succession, males evolve larger testes to produce more sperm and outcompete rivals. Chimpanzees have enormous testes. Gorillas, where one male monopolizes a harem, have tiny ones. Right in the middle again.
Our testicles are telling us we weren't strictly monogamous.
Our testicles are telling a story of moderate sperm competition. Not chimpanzee-level orgies, but not lifetime pair bonds either. And then there's a third line of evidence that gets almost no attention — the ovulatory crypsis problem. Human females don't advertise when they're ovulating. In many primates, there are visible swellings, behavioral changes. Humans conceal ovulation almost entirely.
Which would mean what, exactly? That males couldn't guard fertile windows effectively?
If you're trying to enforce strict monogamy, concealed ovulation makes that extremely difficult. You'd have to guard constantly. But if females benefit from having multiple potential fathers around — either because of paternal uncertainty reducing infanticide risk, or because it creates a broader support network — concealed ovulation is adaptive. It's not proof of non-monogamy, but it's a design feature consistent with it.
The biological evidence points to what — a mixed strategy? Not strictly monogamous, not strictly polygamous, more like "it depends"?
That's the emerging consensus. And "it depends" is actually the key phrase. Because what we see across human societies is extraordinary flexibility. The anthropologist George Murdock looked at over eight hundred societies in his Ethnographic Atlas — and found that over eighty percent of them permitted polygyny, which is one man with multiple wives. But — and this is the crucial part — even in societies that permitted it, most marriages were still monogamous. Polygyny was usually limited to high-status men who could afford it.
Polygyny was common as a permission structure, but monogamy was common as a practice.
And the flip side — polyandry, one woman with multiple husbands — is rare but not nonexistent. You see it in parts of Tibet, the Himalayas, where fraternal polyandry — brothers sharing a wife — prevents land fragmentation in harsh environments where arable land is scarce. It's a practical adaptation, not a sexual free-for-all.
Which brings up something I think gets lost in these debates. When people say "humans aren't naturally monogamous," the assumption is that the alternative is some kind of sexual utopia or dystopia. But the actual alternatives we see in the record are highly structured, rule-bound arrangements. They're not the absence of rules — they're different rules.
That's such an important point. And it connects directly to the second part of the prompt — the legal hypocrisy question. Because you have traditional polygamy, which is heavily regulated, often religiously codified, with clear rules about inheritance, lineage, obligations. And then you have modern polyamory, which is more individualistic, negotiated case by case, and largely ignored by the law.
Yet one faces criminal sanction and the other doesn't. Let's trace that. Where does the legal hostility to polygamy actually come from?
The story that usually gets told is that it's about protecting women from coercion. And there are real concerns there — in some polygamous communities, you see young women pressured into marriages, limited autonomy, the whole patriarchal package. But if you look at the history of anti-polygamy laws in the United States, the story gets uncomfortable fast.
The Morrill Anti-Bigamy Act of eighteen sixty-two wasn't driven by feminist concern for women's welfare. It was driven by a Republican Congress that saw Mormon polygamy as one of the "twin relics of barbarism" — the other being slavery. The federal government essentially waged a legal war on the Mormon church. In eighteen eighty-seven, the Edmunds-Tucker Act disincorporated the church and seized its property. The Supreme Court in Reynolds versus United States in eighteen seventy-nine explicitly framed polygamy as a threat to civilization itself — using language that was frankly orientalist, painting it as a practice of "Asiatic and African people" that had no place in a Christian nation.
The legal framework was built on a mix of religious hostility and cultural supremacy.
It's never really been revisited on principle. Even today, polygamy is a felony in all fifty states. Utah downgraded it from a felony to an infraction in twenty twenty — basically making it equivalent to a parking ticket — but only for otherwise law-abiding adults. The moment there's any coercion or fraud, it jumps back to a felony.
Meanwhile, polyamory — three consenting adults in a relationship, no religious framework, no formal marriage — faces essentially zero legal consequences anywhere. You can't marry multiple people, but you can live with and love multiple people with no legal barrier whatsoever.
Here's where the hypocrisy gets sharp. The state will prosecute a fundamentalist Mormon family for polygamy — even if all parties are consenting adults — but has absolutely nothing to say about a secular triad in Brooklyn. The distinction isn't about protecting women, because both arrangements can be coercive or not. The distinction is about whether the arrangement is religiously coded as foreign and threatening.
It's the "ick factor" dressed up in legal language. Polygamy reads as patriarchal, premodern, religiously alien. Polyamory reads as hip, negotiated, Western, individualist. The law is policing aesthetics, not harm.
We can see this in the way the legal academy has treated it. There's been a wave of scholarship arguing for legal recognition of polyamorous families — multiple-parent adoption, hospital visitation rights, inheritance frameworks. These are serious discussions in law reviews. But polygamy gets almost no sympathetic legal scholarship, despite involving many of the exact same questions about consent, autonomy, and family structure.
The groups that normalize it at the institutional level face hostile laws. The groups that practice it as a lifestyle choice face shrugs. That's the asymmetry the prompt is pointing at.
It's worth asking why. I think part of it is that polygamy challenges the state's monopoly on defining the family. A religious community that builds its entire social structure around plural marriage is making a competing claim about what a family is. Polyamory, by contrast, doesn't challenge the legal institution of marriage — it just ignores it. You can have your three partners and still file taxes as a single person. The state can look the other way.
It's the difference between secession and truancy. One is a threat to the system. The other is just not showing up.
And this is where the history of major religious traditions gets really illuminating. Because the three Abrahamic faiths have had wildly different relationships with polygamy over time — and those relationships have shifted for reasons that are more political than theological.
Let's go tradition by tradition.
Judaism has a fascinating arc. In the Hebrew Bible, polygyny is unremarkable. Abraham has Sarah and Hagar. Jacob has Leah and Rachel — and their handmaids. David and Solomon have multiple wives and concubines. There's no prohibition. The practice continued into the rabbinic period. It wasn't until around the year one thousand that Rabbi Gershom ben Judah issued a ban on polygyny — a takkanah, a rabbinic decree — that applied to Ashkenazi Jews. Sephardic and Mizrahi Jews never accepted the ban in the same way, and polygyny persisted in some Jewish communities in Yemen and North Africa well into the twentieth century.
The ban was geographically limited? Ashkenazi Jews in Europe, but not Jews in the Islamic world?
And the reason matters. Gershom's ban was partly a response to Christian pressure — Jews living in Christian Europe were being denounced for the practice, and it was creating persecution. It was also partly internal — concerns about husbands taking second wives without the first wife's consent. But the key point is that it was a practical decree, not a claim that polygyny was inherently immoral. It was "this is causing problems, stop doing it.
Which is very different from "God commands monogamy.
And in Israel today, the state inherited Ottoman and British Mandate law on marriage. Polygamy is technically illegal, but the law is selectively enforced — particularly among Bedouin communities where the practice has cultural roots. There are cases every year. The state mostly looks the other way unless there's a complaint.
Christianity starts with a clean break from Jewish polygyny — but not for the reasons most people think. Jesus doesn't explicitly condemn polygamy in the Gospels. The shift comes through Paul and the early church fathers, who elevate celibacy as the highest ideal and monogamous marriage as a concession to human weakness. Augustine is explicit — marriage exists to channel lust into procreation, and monogamy is the proper container for that.
It's not that polygamy is condemned — it's that marriage itself is sort of grudgingly tolerated, and polygamy would be too much of a good thing?
That's the early Christian vibe, yes. Marriage as damage control for desire. And within that framework, monogamy made sense — one spouse is already a concession, multiple spouses would be indulgence. But the real hardening came later, when the church became a political institution. The Council of Trent in the sixteenth century declared monogamy the only valid form of Christian marriage — and that was as much about asserting church authority over marriage as it was about theology.
Then there are the splinter groups that went the other way. The Anabaptists at Münster in the fifteen thirties instituted polygamy — though that was under siege conditions and the whole thing collapsed in bloodshed. And of course, the Mormons.
The Mormon story is the one that really shapes the modern legal landscape. Joseph Smith introduced plural marriage as a doctrine in the eighteen forties, framing it as a restoration of Old Testament practice. It was never the majority practice among Mormons — estimates are that maybe twenty to thirty percent of Mormon families were polygamous at its peak — but it became the defining public controversy. The federal government's campaign against it was relentless, and in eighteen ninety, the Mormon church officially abandoned the practice as a condition of Utah's statehood.
The splinter groups that kept it going — the fundamentalist Mormons — are the ones who still face prosecution today.
The institution that was defined by plural marriage now treats it as apostasy.
Islam is the only major Abrahamic tradition that explicitly permits polygyny in its founding text — but with conditions that are often ignored. The Quran, Surah An-Nisa, verse three, says a man may marry up to four women, but only if he can treat them all equally. And then a few verses later, it says "you will never be able to treat them equally, even if you strive to do so." Some scholars read that as effectively a prohibition — permission granted in theory but impossible to fulfill in practice.
It's a permission slip with a built-in self-destruct clause.
That's one reading. Others treat it as a genuine permission with a strong admonition — you can do it, but the bar is high. In practice, polygyny rates in Muslim-majority countries vary enormously. In some Gulf states, it's more common. In Turkey and Tunisia, it's banned entirely — Tunisia's ban dates back to nineteen fifty-six, and it was justified on exactly that Quranic reasoning about the impossibility of equal treatment. In Indonesia, it's legal but bureaucratically difficult — you need the first wife's consent and court approval.
The legal landscape globally?
About fifty countries permit polygyny in some form, mostly across the Sahel region of Africa, the Middle East, and parts of South and Southeast Asia. But even in countries where it's legal, it's usually a minority practice. And the trend line is toward restriction — many countries that permitted it have tightened laws over the past century.
Here's the thing that strikes me. In all three traditions, the conversation is almost exclusively about polygyny — one man, multiple women. Polyandry barely registers. Even the word "polygamy" is used as a synonym for polygyny. The asymmetry is baked into the language.
That's not a coincidence. These are patriarchal traditions — they're concerned with controlling women's reproduction and ensuring clear lines of patrilineal inheritance. A man with multiple wives produces children whose paternity is certain. A woman with multiple husbands creates ambiguity. The entire legal and theological apparatus is built around that anxiety.
The religious hostility to non-monogamy isn't about non-monogamy per se. It's about controlling female sexuality and securing inheritance.
That's a strong claim, but I think the historical record supports it. Even the rabbinic ban on polygyny was partly driven by inheritance disputes — multiple wives meant competing claims from multiple sets of children. The law prefers clarity.
Let's pull on the inheritance thread. Because that's where the state's interest in marriage actually comes from. Marriage isn't just about love or companionship — it's a property regime.
And this is the materialist explanation for why states favor monogamy. Monogamous marriage produces clear lines of descent. Property passes cleanly from one generation to the next. There's no ambiguity about which wife's children inherit what, no competition between branches of a polygamous household. The state wants legible families.
That's the phrase. A polygamous household with four wives and twenty children is a bureaucratic nightmare. Who's the next of kin? Who makes medical decisions? Who inherits the house?
Polyamory creates the same problems but even more so, because there's no standardized framework at all. If three people are in a committed triad and one of them is hospitalized, the other two have no default visitation rights. If one dies, the surviving partners have no inheritance rights unless there's a will. The law simply doesn't have categories for these relationships.
Which is why you're seeing the push for legal recognition. But that push is coming from secular polyamorists, not religious polygamists. And the reception is different.
It's different because the aesthetics are different. A polyamorous triad in Portland reads as progressive. A polygamous Mormon family in Utah reads as reactionary. The behavior is structurally similar, but the cultural coding is opposite.
The glockenspiel of corporate approachability versus — what's the polygamy equivalent? The banjo of rural suspicion?
Something like that. The banjo of threatening otherness.
We've got a legal system that punishes religious non-monogamy and ignores secular non-monogamy. And we've got three major religious traditions that all converged on monogamy for reasons that are more political and practical than theological. What does the actual evidence say about how well monogamy works — or doesn't — as a social arrangement?
That's the deeper question. And it's where the evolutionary anthropology gets really interesting. Because monogamy is unusual among mammals — only about three to five percent of mammalian species form pair bonds. It's even less common among primates. And when it does emerge, it's usually not because males suddenly decided to be faithful.
What drives it, then?
The leading theory is that monogamy evolved as a strategy to reduce infanticide. In many primate species, when a new male takes over a group, he'll kill the nursing infants. A lactating female won't ovulate, so killing her infant brings her back into fertility faster. But if a male bonds with a specific female and protects her offspring, his genetic investment is secured. Monogamy, in this view, is a paternity protection racket.
Monogamy isn't about love or morality. It's about males not murdering each other's babies.
That's the unromantic version. There's a competing theory — the pair-bonding-as-provisioning model — where monogamy emerges because human infants are so helpless and require so much investment that two parents are better than one. But that doesn't explain why the pair bond needs to be sexually exclusive. You could have two parents cooperating without sexual exclusivity.
We do see that in some societies. The Mosuo people in China, for example — they practice what anthropologists call "walking marriage," where women live with their natal families, men visit at night, and children are raised by the mother's family. There's no expectation of sexual exclusivity, and paternity is basically irrelevant.
The Mosuo are a fascinating case. And they're not alone. There are matrilineal societies in various parts of the world where the mother's brother plays the role that a father would play in a patrilineal system. The nuclear family isn't a human universal.
Which brings us back to the core question. If monogamy isn't biologically hardwired, if it's not theologically mandated in any clear way, if it emerged for practical and political reasons — why do we treat it as the only legitimate option?
I think there's a few layers. One is simple path dependency. Monogamy became the norm in Europe, European colonialism spread it globally, and now it's baked into international law and human rights frameworks. The Universal Declaration of Human Rights says men and women have the right to marry — singular. The assumption is monogamy.
The second layer?
The second is that monogamy does solve real coordination problems. It simplifies inheritance, it reduces male-male competition, it creates clear household units that the state can tax and regulate. From the state's perspective, monogamy is just easier to administer.
It's not that monogamy is morally superior. It's that monogamy is administratively convenient.
That convenience gets moralized after the fact. The state prefers monogamy because it's legible, and then we tell ourselves stories about how monogamy is natural and virtuous to justify the preference. The stories come after the policy, not before.
That's a pretty jaundiced view of the whole enterprise.
I'm a retired pediatrician — I've seen too many families to be romantic about institutions. But I'm not saying monogamy is bad. For many people, it works beautifully. The problem is the pretense that it's the only thing that works, or that it's what humans are "supposed" to do.
That pretense has real consequences. The prompt mentions religious groups facing hostile laws. We're not talking about abstract debates — we're talking about families being prosecuted, children being taken from parents, communities being driven underground.
The Short Creek raid in nineteen fifty-three is the starkest American example. Arizona state police raided a fundamentalist Mormon community, arrested hundreds of people, and took over two hundred children into state custody. The photographs of mothers holding up signs for their children through chain-link fences — it was a humanitarian disaster. And it was all done in the name of enforcing monogamy.
The justification was protecting women and children. But the intervention itself caused enormous trauma.
Which is the recurring pattern. The state claims to be protecting the vulnerable, but the enforcement mechanism is often more harmful than the practice it's targeting. And that's where the hypocrisy really bites — because if the concern were about coercion and exploitation, we'd see similar scrutiny of monogamous marriages where those things happen. But we don't.
Because monogamous marriage is the default. Coercion within monogamy is just a bad marriage. Coercion within polygamy is a crime.
That's the asymmetry in a nutshell.
Let me ask you something that's been in the back of my mind through all of this. If the science says we're flexible, and the history shows monogamy is a practical arrangement that got moralized after the fact, and the legal system is hypocritical in how it treats different forms of non-monogamy — what's the actual argument for keeping things as they are? Is there a case for monogamy that isn't just "this is what we're used to"?
I think there is. And it comes from a direction that might surprise you — it's about inequality. There's a body of research suggesting that when societies shift from monogamy to polygyny, one of the predictable effects is that wealthy, high-status men accumulate multiple wives, and lower-status men are left with no marriage prospects at all. That creates a pool of unattached young men, which — historically — is a recipe for social instability.
The surplus male problem.
In societies with high levels of polygyny, you see higher rates of violence, crime, and political instability. The argument — and it's been made by scholars like Joseph Henrich — is that normative monogamy reduces male-male competition, lowers the stakes of mate competition, and creates broader social cohesion. It's not that monogamy is morally superior — it's that it produces more stable societies.
Monogamy as a kind of resource equalization mechanism. Spread the reproductive opportunity around.
Crudely put, but yes. And there's some cross-cultural evidence for this. In polygynous societies, the age gap between husbands and wives tends to be larger — older men accumulate younger brides, younger men are shut out. In monogamous societies, the marriage market is tighter, and men marry closer to their own age. It creates different social dynamics.
That's a consequentialist argument, not a moral one. And it only applies to polygyny, not to other forms of non-monogamy. If you've got a closed triad of three people, or a polyamorous network where everyone has multiple partners, you're not creating a surplus male problem.
The instability argument is specifically about polygyny — and specifically about high levels of polygyny, where it's common enough to distort the marriage market. The low levels of polygyny we see in most societies where it's permitted don't produce those effects.
We're back to the hypocrisy. The legal system isn't making these distinctions. It's just painting all non-monogamy with the same brush — unless it's secular, in which case it's invisible.
I think that's where the prompt's framing is so sharp. The question isn't "should the state recognize polyamory." The question is why the state simultaneously criminalizes one form of non-monogamy and ignores another. And the answer, as far as I can tell, is that the law is downstream of cultural aesthetics, not principle.
The law is downstream of the ick factor.
The ick factor, and a history of religious hostility that never got honestly reexamined. The anti-polygamy statutes on the books in the United States are a direct legacy of the nineteenth-century campaign against Mormonism. They've never been justified on their own terms — they've just persisted because nobody wants to have the conversation.
Because having the conversation means admitting that the emperor has no clothes. That the legal preference for monogamy isn't grounded in anything more solid than "this feels normal to us.
"this feels normal to us" is a terrible basis for criminal law.
Let's talk about the modern landscape for a moment. Because polyamory and consensual non-monogamy are having a cultural moment. There's survey data on this.
A twenty sixteen study in the Journal of Sex and Marital Therapy found that about one in five Americans have engaged in consensual non-monogamy at some point. A twenty seventeen study estimated that four to five percent of Americans are currently in a consensually non-monogamous relationship. That's not a tiny fringe — it's millions of people.
It skews younger, more educated, more urban, less religious. No surprise there. But it's not just a coastal elite phenomenon — you find polyamorous communities in most major cities. There are conferences, there's a whole vocabulary — compersion, metamour, nesting partner. The subculture has built an entire alternative framework for thinking about relationships.
That's the word for feeling joy at your partner's joy with someone else? The opposite of jealousy.
And whether you find that admirable or implausible probably says more about you than about the people practicing it. But the point is that this is a growing subculture with its own norms, its own ethics, its own language. And the law has nothing to say about it.
Because it doesn't threaten the institution of marriage. These people aren't asking the state to recognize their triads as marriages. They're just living their lives.
That's the ultimate dodge. The state can tolerate non-monogamy as long as it doesn't ask for recognition. The moment you want hospital visitation rights or inheritance protections, you're making a claim the system isn't built to handle.
Which is where the religious groups actually have a stronger claim, in a way. They're not just asking for tolerance — they're asking for recognition. They're saying this is our family structure, it's institutionally codified, it's been practiced for generations, treat it as legitimate.
The state says no — precisely because it's institutional. Because recognizing religious polygamy would mean acknowledging an alternative family structure that challenges the state's monopoly on defining marriage. Secular polyamory doesn't challenge that monopoly because it doesn't ask for anything.
The hostility is proportional to the threat. Polyamory is invisible, gets no hostility. Religious polygamy is institutional, gets crushed.
The people caught in the middle are the ones who suffer. The fundamentalist Mormon families who aren't coercing anyone, who are just trying to live according to their beliefs. The Muslim families in countries where polygyny is legal but who face social stigma and bureaucratic barriers. The polyamorous families who can't visit their partner in the hospital because they're not legally "family.
It's a mess. And I don't think there's a clean solution. But the first step is just being honest about what's actually driving the policy. And it's not principle.
It's almost never principle. It's history, aesthetics, and administrative convenience wearing a moral mask.
And now: Hilbert's daily fun fact.
Hilbert: Naked mole rats have translucent skin on their undersides, which allows the light from bioluminescent fungi in their tunnels to cast a faint, ghostly glow through their tissues — a property that medieval chroniclers in the early period described as "the walking lantern of the earth," though no such creature was ever confirmed in Belize.
The walking lantern of the earth. That's a D and D monster waiting to happen.
I have so many questions about medieval chroniclers and naked mole rats, and I'm going to suppress all of them.
Alright — so where does this leave us? I think the prompt forces a reckoning that most people don't want to have. The science says humans are flexible, not hardwired for monogamy. The history shows that monogamy became dominant for practical and political reasons, not moral ones. And the legal system enforces it selectively, targeting religious non-monogamy while ignoring secular non-monogamy. The whole thing is a patchwork of unexamined assumptions.
I think the most honest thing we can say is that there's no single human mating system. We're a species that adapts our relationship structures to our environment, our economy, our ecology. Monogamy works well in some contexts. Other arrangements work well in others. The impulse to declare one correct and the others deviant is a political impulse, not a scientific one.
The question going forward is whether the legal system will ever catch up to that reality — or whether we'll just keep pretending that the current arrangement is natural and just, because it's easier than having the conversation.
My guess is that change will come from the secular side first. Polyamorous families are already pushing for legal recognition in areas like domestic partnership ordinances, and those battles are happening at the municipal level. The religious cases are harder, because the cultural coding is so loaded. But if the principle is consent and harm reduction, the distinction between religious and secular non-monogamy becomes harder and harder to defend.
That's the open question. Whether we can build a legal framework that actually evaluates relationships based on consent and welfare, rather than on whether they look like what we're used to. I'm not holding my breath — but I think the conversation is worth having.
It's definitely worth having. And I'm glad the prompt pushed us to have it.
Thanks to our producer Hilbert Flumingtop for keeping this show running and for whatever dark corner of the internet he pulled that naked mole rat fact from. This has been My Weird Prompts. You can find more episodes at myweirdprompts dot com or wherever you get your podcasts. We'll be back next week.
