Are men really hardwired to be less monogamous than women?
This week, a psychiatrist faced a tribunal after telling a female patient that men, unlike women, are not biologically programmed for monogamy. But is he right? We delve under covers
It's a question as old as the sun: are men naturally monogamous?
This week, the evolutionary conundrum cropped up once again when it was reported that a Southampton-based psychiatrist Dr Joseph Bray told a female patient seeking guidance after discovering her husband's extramarital affairs that "to expect fidelity in marriage is an unreasonable expectation".
The ongoing court case will decide whether Dr Bray was right to do so in his professional capacity as a psychiatrist. But away from the doctor's office, was he really just speaking the truth?
Modern records certainly back up Bray's claim. Alfred Kinsey's famous 1948 and 1953 sex studies found that 50 per cent of US men sought sex outside of marriage at some point.
And it's a figure that has stayed relatively static over the years. Dr Katherine M Hertlein, Professor of Human Development at the University of Nevada, puts the number at 40pc through her extensive work on infidelity and the internet.
These statistics are not without logic. Evolutionary psychologist David M Buss, Professor of Psychology at the University of Texas and author of The Evolution of Desire: Strategies of Human Mating, says men are simply wired to seek out as many female partners as possible.
According to Buss, men have "evolved the desire to be with different women" because there is simply no biological barrier in place stopping a man procreating with as many women as possible. Men have limitless sperm compared to the limitations on women and their eggs; men can effectively have back-to-back babies whereas women have to wait nine months in between each birth; men can up and leave, whereas women are in for the long haul.
As a result, men are programmed to expand "their genetic legacy by spreading their cheap seed, while females are inherently made to maximise their investment by being choosy, by securing a male likely to be a good long-term provider".
New York Times writer Daniel Bergner, author of What Do Women Want? Adventures in the Science of Female Desire, doesn't subscribe to such a narrative. He believes women aren't "evolutionary scripted" to be monogamous, but are "culturally caged".
"Let's accept for a moment what seems, from a growing number of original studies on desire, perhaps true: nature hasn't made women for monogamy at all, that women's desire may well be oxygen-starved, if not suffocated, by constancy," he argues.
Meredith Chivers, a psychologist at Queen's University in Ontario, Canada conducted one of these "original studies". Chivers examined the genital reactions of women whilst she played them erotic audiotapes of two subtly different sexual liaisons - one with a handsome male stranger, the other with a hunky male friend. In most cases, the stranger got the tick.
Likewise, in her book Why Women Have Sex, Professor Cindy Meston of the University of Texas explores why masculine faces, certain scents and deep voices play a pivotal role in women's monogamous and non-monogamous intentions.
In one study she cites, 142 heterosexual women listened to the recordings of male voices and rated each one on attractiveness for one-night stands or long-term commitment. Deeper voices were considered sexually superior, particularly for women in the fertile phase of their ovulation cycle.
"Bilateral body symmetry," Meston explains, "is commonly accepted as a sign of good health and good genes. Body symmetry is also more likely to produce deep voices. So when a woman finds the resonance of a man's voice even sexier during her fertile, ovulatory phase, she is attracted to the sound of healthy genes for her possible offspring."
In other words, women seek out men with deep voices (Superman-style jaws and subliminal displays of high testosterone) to, in effect, sow their wild oats.
In a clear mirroring of intent across the gender boundaries, such evidence reflects the way in which men may seek younger females for affairs revealing that, likewise, women are more inclined to seek masculine men for fleeting romances as well. So the next time you catch the missus ogling the pool guy, don't blame her, blame her genes instead.
Tim Birkhead, Professor of Evolutionary Biology at the University of Sheffield goes one step further in his book Promiscuity: An Evolutionary History of Sperm Competition.
"By being promiscuous, women can also ensure greater care for their children," he says, giving the example of the Inuit people of Arctic North America who partake in 'co-marriage' (two couples marrying each other) as a means to ensure children have two sets of parents to look after them in the life-threatening conditions of the Arctic.
Thus proving that non-monogamy doesn't always have to be driven by perfunctory carnal desires. Passionless polyandry can also be incredibly beneficial for evolutionary reasons, namely, making sure your genes stay in the game.
When it comes to the ways in which we allow our desires to lobby our actions, the glue that holds evolutionary biology and non-monogamy together may well be invisible but it is also extremely strong. And, seemingly, it doesn't discriminate between genders.
"One of our most comforting assumptions - soothing perhaps above all to men, but clung to by both sexes - that female eros is much better made for monogamy than the male libido," Daniel Bergner concludes, "is scarcely more than a fairytale."