According to Wednesday Martin, if you want to know how early humans organised their sex lives, before prudery, habit and agrarian production got in the way, you should take a look at bonobos. Once known as pygmy chimps, these primates are the closest thing we have to a living ancestor. Certainly, they resemble us more than the common chimp. They are fine-boned, with pink lips, proportionately long legs on which they can walk upright and hair that falls into a neat centre parting.

However that prissy hair-do is misleading. Bonobos are, as is well known, shameless sexual gluttons, especially the females. They wander around in a girl gang and, when they fancy a bloke, go up and put their arm around him. If he moves away the female follows him for a bit. Pretty soon, though, she gets exasperated by his coyness and turns to one of her girlfriends instead. Together they have a lovely time, rubbing their enlarged clitorises together, with murmurs of pleasurable excitement. If a boy wanders up at this point, he’s likely to be seen off with an exasperated nip for being far too late to the party.

Martin argues that we should all be a bit more bonobo (minus the nipping, obviously). Our cousins can teach us a lot about how human sexuality operated before it was corralled into an essentialist narrative about men being “naturally” polygamous while women “instinctively” seek out their one and only. Of course, this call to revision is not uniquely Martin’s. Although she has a PhD in anthropology from Yale, she remains a journalist, reporting and synthesising the work of such pioneering fieldworkers as Sarah Blaffer Hrdy, Meredith Chivers, Alicia Walker, Cacilda Jethá and many more.

A one-week-old baby bonobo with its mother. Photograph: François Lenoir/Reuters

Some of Martin’s authorities, such as Brooke Scelza of UCLA, work with human subjects. Scelza’s research on the semi-nomadic Himba tribe of Namibia provides a window into alternative ways of dealing with what anthropologists call “extra-dyadic sexuality” (AKA consensual cheating). With the Himba men periodically away at remote cattle stations, their wives keep busy by “going to the far place to collect water” – another way of saying they bunk off to meet their lover. If a baby is the result, no one sees any reason to fuss: the child will simply have two dads (AKA partible paternity). Indeed, Scelza reveals that those Himba women who are particularly keen on going to collect water end up with more and healthier children than those few who to decide to stay “true” to their husbands. Might we actually be looking at a state of affairs, Martin asks, where, from an evolutionary point of view, a woman’s insistence on monogamy starts to seem just the tiniest bit selfish?

Those who have a nodding acquaintance with work on what evolutionary biologists call “female choice” will doubtless be worried that Martin has simply cherry-picked the examples that support her argument, while passing silently over all those thousands of studies that don’t show research subjects behaving in ways we’re used to: prudent egg-guarding females, and splashy seed-scattering males. One also wonders whether this material, invigorating though it is, quite counts as the “new science” that is trumpeted by the publicity. Some of this work, including that by the pioneering biologist Hrdy, dates back to the 1980s.

The tone and structure are awkward, with the interviews with academics mixed with case histories of women who have chosen to break cultural taboos by openly sleeping with a secondary partner while retaining their primary relation (the trick is being handy with shared Google calendars). But the problem with these mostly pseudonymised case histories, in which, Martin tells us, “I have changed many specifics”, is that they sit uncomfortably alongside reports of scholarly work where to change a “specific” would be to invalidate the whole process. Indeed, after an earlier book, Primates of Park Avenue, about life in New York, Martin faced criticism for playing around with details.

One also wonders whether this material counts as the 'new science' that is trumpeted by the publicity

What are the rules for this kind of popular reportage? To stick to the factual record while protecting privacy through anonymising the case histories, which is how it works in academic science, would be to sacrifice any hope of the work being “relateable” to the general reader. And relateability – the call to rethink one’s own dilemmas by hearing about others’ – is the engine that drives Untrue.

Martin’s own attempt at fieldwork is marked by a counterproductive coyness. In particular she simmers over something called the Skirt Club, a gathering where carefully invited straight women meet for a night of lesbian sex. Everyone seems to be clean and rich and thin. Eventually Martin wangles an invitation – we knew she would – and proceeds to describe toe-curling encounters along the lines of “her breasts strained against the plunging neckline of her tight nude pleather dress”. By which time we have strayed a long way from “female choice” and into a novel by Jackie Collins.

• Untrue: Why Nearly Everything We Believe about Women, Lust and Infidelity Is Untrue is published by Scribe. To order a copy for £12.89 (RRP £14.99) go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.