If you want a template for enlightened sexual mores, look to our ape ancestors—at least that appears to be the emerging consensus among some of America’s bien pensants. “[Bonobos] have sex to say hello, they have sex to say goodbye, they have sex when they’re stressed out,” says author Christopher Ryan in a new 18-minute documentary, “Monogamy, explained.”

Produced by Vox and hosted on Netflix, the mini-doc is in fact more interested in deconstructing monogamy than in explaining it. Like many other recent think pieces on the subject, “Monogamy, explained” underscores the perceived virtues of consensual non-monogamy.

Polyamory, we’re told, is natural. Monogamy is not. From an evolutionary standpoint, more mates meant more reproduction and survival of the species. And, as the heirs of bonobos, humans too yearn for promiscuity. The message seems to be: embrace your nature—go forth, explore. “If we’re lucky,” the documentary says, “it’s no longer about what relationship we should have in the modern world; it’s about designing the kinds of relationships we want to have.”

Any doubts about the wisdom of normalizing promiscuity in an era when so many children are already born out of wedlock are presumably addressed by large helpings of birth control and the word “consensual.” This word, as vital as it is, patches over the many conflicts that arise when people with vastly different visions of sexual desire are empowered to pursue the couplings they “want to have.”

Colleagues at Brigham Young University have already exposed the shaky methodology behind studies that paint consensual non-monogamy in overly rosy hues. But appeals to bonobo behavior to justify non-monogamy demand similar scrutiny.

The study of apes can provide helpful scientific insights into human health—after all, we do share a significant portion of DNA. But looking to bonobos as co-architects of modern systems of morality is a troubling trend that should worry anyone who still values stable households and sexual fidelity.

Christopher Ryan, who appears in the Vox documentary, is co-author of Sex at Dawn, a book that draws heavily on bonobos to make the evolutionary case for non-monogamy. But the book is not alone in offering bonobos as a blueprint for behavior. Frans De Waal’s Bonobo: The Forgotten Ape first proposed bonobos as a possible model in the late 1990s.

“The bonobo,” writes De Waal, “with its varied, almost imaginative, eroticism, may help us see sexual relations in a broader context. Certain aspects of human sexuality, such as pleasure, love, and bonding, tend to be overlooked by reproduction-oriented ideologies.” He proposes that this revised human history has “serious implications, given how often moralizing relies on claims about the naturalness or unnaturalness of behavior: what is natural is generally equated with what is good and acceptable. The truth is that if bonobo behavior provides any hints, very few human sexual practices can be dismissed as ‘unnatural.’”

The argument is alluring: Bonobos are promiscuous; humans evolved from bonobos; since many humans want to be promiscuous, this propensity for promiscuity probably arises from inherited impulses. Consequently, humans should not be stigmatized for indulging in non-monogamous behavior that they are hardwired to pursue.

In this vision of morality, it is in fact the monogamous who are, to borrow a biblical phrase, “without natural affection.” But this argument gives rise to a series of menacing questions. How far do bonoboite boosters want to take us? What human vices can and should be blamed on bonobos, and what behaviors are still attributable to human volition?

Bonobos are not, after all, merely promiscuous. They engage in sexual contact with juveniles, infants, and close relatives. And though they are esteemed in feminist circles for their strong “female camaraderie,” they are often violent and sometimes merciless. Though generally more peaceful than male-dominant chimpanzees, bonobos organize hunting parties in which females and males kill fellow monkeys or eat them alive. Surely humans should not indulge any of those behaviors. Nor should we honor the bonobian preference, described by recent research, for anti-social dominant behavior rather than altruism.

So which primate behaviors should we accept as innate and justified, and which should we eschew? And another question arises, which those sympathetic toward consensual non-monogamy seem unprepared to answer: what is the relation between evolutionary determinism and human free will?

Bonoboite boosters claim that humans evolved to be non-monogamous and thus should not be stigmatized for promiscuity they can’t control. I agree that we should stigmatize a bit less and bestow grace a bit more. However, the irony here is the assumption that humans have plenty of control over who they stigmatize, but very little control over with whom they copulate. Indeed, modern Americans have enough free will to design the kinds of relationships they“want to have,” but perhaps not enough to remain faithful to a singular mate.

If humans are free to design their destinies, it seems they should strive toward their “better angels” rather than their baser bonobos. So are we designers, or are we determined? Are we automatons, or are we autonomous?

William Jennings Bryan’s famous question before the Scopes monkey trial may have been little more than an applause line, but today it reads like a haunting plea from an America caught between cultures: “How can teachers tell students that they came from monkeys and not expect them to act like monkeys?”

Hal Boyd is visiting fellow at the School of Family Life at Brigham Young University.

