Thu Mar 14

Why is the male body the scientific default when the female body drives the reproductive success of our species?

Written by: Edwina Preston, PhD Candidate, The University of Melbourne

American essayist Cat Bohannon loves a bit of pop culture to contextualise her ideas. Eve: How the Female Body Drove 200 Million Years of Human Evolution ^[1] – her ambitious, funny, intelligent history of female evolution – is threaded with it.

The book opens with a futuristic scene from Prometheus ^[2], the 2012 prequel to Alien ^[3]. Archaeologist Elizabeth Shaw is in an AI surgery pod, seeking a life-saving caesarean (she has been impregnated with an alien squid) when an affectless voice gives her an error message: “This medpod is calibrated for male patients only.”

Crash-test dummies, heart-attack symptoms, anti-depressant dosages, air-conditioning systems in large office buildings: we are all pretty aware by now that these are “calibrated for male bodies only”. Alien Prometheus is set in 2093; one can only hope the scientific technology of the late 21st-century turns out to have, at least, a “female-registering” option.

Eve: How the Female Body Drove 200 Million Years of Human Evolution – Cat Bohannon (Hutchinson Heinemann)

While women’s hormonal cycles have made us messy in the arena of “clean science” – not good controls, not good at being controlled for – Bohannon reminds us that an understanding of the female body cannot be retrofitted to an understanding of the male body. Women are not just men with extra fleshy bits and confounding hormones. Bohannon also reminds us those “fleshy bits” have a function beyond providing a curvaceous silhouette. Female adipose tissue, 600 million years old, stored around our butts and thighs, is necessary to the development of babies’ brains. It is so necessary that girls begin storing it in childhood and when women liposuction it out of their lower bodies it returns in unexpected places: the armpits, for example. Bohannon points out that the possible repercussions of liposuction on the brain health of future offspring has not yet been studied. Read more: Women have heart attacks too, but their symptoms are often dismissed as something else ^[4] Reproductive success The salient question here is: why is the male body the scientific default when it is the female body that crucially drives the evolution and reproductive success of our species? Eve is both a rectification of this immense blind spot and, in Bohannon’s own words, “a user’s manual for the female mammal”. Yet how to collapse 200 million years of evolutionary history into 500 pages (let alone 1500 words)? Bohannon does this by organising her book into a series of “Eves” from whom we inherited our current biological functions, creating an often diverging, often interlocking chronology. There is the Eve of milk, “the real Madonna”; placental Eve, “an HR Giger fever-dream meat factory” (Bohannon has fun with language); Donna, Eve of the uterus; and Pergi, the tree-dwelling Eve of perception. This structure allows Bohannon to move from microbiology to paleoanthropology, evolutionary biology to gynaecology, anatomy to social history. I learnt much about my own body in her sprawling, illuminating discussions, but also about animal reproductive biology in general — from monotremal cloacas (platypuses and echidnas have them) to squamation hemipenises (snakes and lizards) and “notoriously foldy” anti-rape duck vaginas designed to circumvent corkscrew penises. It was some small relief to learn the fairly straightforward design of the human penis is testament to a “not-particularly rapey” human evolutionary history.

‘Notoriously foldy.’ Image: Roger Heslop, via Wikimedia Commons, CC BY ^[5]^[6] Bohannon writes with tender care of her “Eves”. She manages to both penetrate and animate deep time for the reader, a textual equivalent perhaps of Walking with Dinosaurs. She describes the Jurassic insect-eater Morgie ^[7] (my favourite), one of the earliest known mammals, skittering over the feet of dinosaurs to get home to her burrow, where she sweats milk through mammary patches to feed her hidden brood. Morgie comes vividly alive in her small precarious existence: “funny, warm, heart-fluttering Eve”, Bohannon writes. For a female with a uterus, who has twice given birth and twice breastfed, Bohannon’s book demystified many of the mysterious goings-on of my reproductive system. I had no idea, for instance, that lactation was such an intensive co-production between mother and baby. I knew it enabled a baby’s gut to be colonised with good maternal bacteria, and I knew the basic mechanics of the let-down reflex. But I didn’t know that the composition of the milk itself is informed by a baby’s needs. These needs, codified in a baby’s saliva, are registered by the mother’s body, which then customises its milk accordingly, so it is full of the particular bacteria- or virus-fighting agents required. This recriprocity is also apparent in the biological wonder that is the placenta. Built out of both endometrial and embryonic tissue, the placenta is “one of the only organs in the animal world made out of two separate organisms”. Did you know this? I certainly didn’t.

‘Morgie’ – Morganucodon, one of the earliest known mammals. FunkMonk (Michael B.H.), via Wikimedia Commons, CC BY-SA ^[8]^[9] Read more: A raunchy new 'Big History' tells the story of sex, but raises some unanswered questions ^[10] Life: a user’s manual In this sense, Eve really is a user’s manual. At the risk of sounding “miracle of life” about it, Bohannon’s book puts wonder into the commonplace by explaining not only how our reproductive systems work, but how they came to be. Women’s bodies are not just about babies, of course. Bohannon charts new political territory, tracing her anatomical discoveries through to their social outcomes. Truisms of human and social evolution are turned on their heads and gynaecology gets its rightful place in the story. Milk again: the population growth that enabled humans to become the ferocious planet-hogs we are today might be down to the humble wet-nurse of ancient civilisations. The prevalence of wet-nursing meant the natural contraceptive properties of breastfeeding were not in play for many women. This meant women had much shorter spaces between pregnancies and had more babies. Wet-nurses, those under-sung footnotes in history, might well have catalysed the growth of modern cities. Bipedalism? It might just be that we stood up on two feet not so we could better carry spears, but so we had free arms to carry babies while hunting and still cart as much food home with us as possible. Tool-making? The seminal moment here may not have been a Kubrick-style raising of a femur bone to crunch down on a challenger’s head, or beat an animal to death for dinner (fossil remains show we really didn’t eat a particularly intensive paleo diet). Instead, it might have been a woman, baby on back, chewing a sapling to a neat point to hunt “bush-babies ^[11]” asleep in tree hollows. Bohannon makes a good argument that it was women, not men, who most needed tools to hunt. Our biologically stronger male counterparts often needed only the heft of their bodies to bring down an animal. Women were inventors, she says, because, being smaller, being weaker, they had more need.

Cave painting depicting a woman giving birth, Serra da Capivara national park, Brazil. Vitor 1234, via Wikimedia Commons, CC BY-SA ^[12]^[13] Read more: Friday essay: matrilineal societies exist around the world – it's time to look beyond the patriarchy ^[14] Womb triumphalism Our most important invention, though – and this is the overarching thesis of Bohannan’s book – is gynaecology. “What got us here,” she writes, “is not tool triumphalism but womb triumphalism.” Considering how hard it is for the human female body to get pregnant, stay pregnant, deliver a baby (without us or it dying), and then look after it through its protracted childhood, it is a miracle that humans populate – and over-populate — the planet in the way we have come to. Gynaecology, Bohannon writes, is absolutely essential for our species’ evolutionary fitness. Without it, it’s doubtful we would have made it this far […] The arrival of midwifery is one of those moments when we can truly say, “Here is when we become human” […] No other mammals on the planet have been observed regularly helping one another give birth. With gynaecology comes contraception, reproductive choice and birth-spacing. Knowledge about the properties of herbs and plants, about labour, about delivering a breech or posterior baby, or really any baby (they are all life and death situations) – all of these combine to enable the flourishing of humans, in spite of our large heads, narrow pelvises, complex gestation and birthing trajectories. “Women had their hands on the actual machinery of evolution,” Bohannon writes. And while she notes that “[m]odern female coalitions are scattered, vulnerable, brittle”, her book celebrates the ancient collaboration between women and the spirit of cooperation over competition that got us here. Bohannon repositions this as profound in its significance for the human race. A failure to fully apprehend the different workings of male and female bodies and not provide for these differences – or to provide comprehensively for one sex, and neglect the other – doesn’t just mean there will be no caesarean option in a future surgery-pod. It means limiting human possibility and opportunity. It represents a failure to grasp the whole human story and its potential. Bohannon ends her book with a practical feminist statement about the importance – and boon to society – of educating women, feeding them properly (not last), and putting financial means in their hands. Smart humans of the future – who might want to flourish without destroying the means of their flourishing – will require women with adipose fat to feed the brains of their suckling babies, with reproductive choices to plan and space those babies, and with life choices which enable them to contribute their full potential to the world.