Boundary marking gender difference becoming blurred

By BOB BEALE

From the moment a child is born, the cry of "It's a boy" or "It's a girl" marks its most basic label of personal identity.

But our understanding of sex and gender is undergoing profound and surprising changes thanks to insights gained from biology, sociology, medicine and technology.

When it comes to the differences between females and males, what once seemed black and white - or pink and blue - now seems a shifting zone of confusion.

For starters, there's evidence that men and women are hard-wired from birth to differ in subtle and intriguing ways when it comes to behaviour. In effect, children may be born sexist.

More than a few feminist mothers, for example, have been forced to concede defeat in trying to deter their own sons from rough play, wanting toy guns and risk-taking.

It is well documented that boys and girls segregate themselves and learn different ways of interacting socially early in their lives.

The distinguished American developmental psychologist Eleanor Maccoby contends that nature usually gets too little credit for that process of separation.

While she agrees that gender is largely a product of cultural forces, she argues that male-female distinctions come into play so early in childhood and are so universal that they must be deeply grounded in our biology.

The tendency to prefer same-sex playmates becomes progressively stronger through the preschool years, until by primary-school age it is powerful indeed, says Maccoby in her landmark book, The Two Sexes: Growing up Apart, Coming Together.

Tellingly, this happens in societies across the world, virtually regardless of individuals' social experience, family background and the degree of gender segregation that happens in the adult world around them, she says.

Children raised by single parents and lesbians or consciously raised in a gender-neutral way from birth exhibit the same gender stereotype. Most children can distinguish the sexes by the time they start learning to walk and talk, within a year of birth.

By age 3, most can use correct gender labels for themselves and others. Though they may still form strong friendships with members of the opposite sex, it is at this age that mixed-sex groups start to segregate themselves into boy or girl sub-groups.

By 6, most children seem drawn into peer groups and friendships with children of the same sex. Maccoby believes that gender is not so much an individual trait as a property of social groups. When individual boys and girls are alone, their behaviour does not observably differ all that much, she says, but when they gather in same-sex groups they differ radically.

Boys in groups focus on competition and pecking orders, with lots of shows of bravado and confrontations, whereas girls in groups tend to collaborate as equals, with more empathy and cooperation and, often, more talk of feelings.

Boys who try to socialise with girls are quickly noticed and pressured not to do so by other boys, who monitor the boundaries of their groups. Girls who try to socialise with boys are often repelled by rough, self-centred male play styles.

They may learn at least some of their gender segregation from older children. Adults seem to have little initial influence, although parents, teachers and popular culture can probably temper or reinforce these trends as children grow older.

If it sounds far-fetched to suggest that children may have a special sexist culture to match their sexist biology, Maccoby points out that other children-only cultures exist.

Games, for example, pass down through generations. One study in the 1960s found that British children still played some games dating back to the time of Roman occupation.

But a contrary message is emerging from genetic studies: they suggest that men and women have much more in common than they have differences. So far as we know, out of the estimated 31,000 genes in the human genome, the only genetic differences between women and men are found on the two sex chromosomes - known as X and Y - and even then only a few dozen genes seem involved.

Science is starting to reveal in extraordinary detail how genes determine the sex of a foetus and how that process can and does go awry. Andrew Sinclair, who heads the Centre for Hormone Research at the University of Melbourne, was part of the British-based team that in 1990 discovered a crucial gene, known as SRY, that usually occurs only on the male Y chromosome of all mammals.

Take SRY alone and inject it into a fertilised female mouse egg and it will become a male, as other researchers at Britain's National Institute for Medical Research later showed.

The animal in question was aptly nicknamed Randy and he was the first sex-reversed mouse produced in this way. His testes were small but he otherwise grew up male in every discernible way, despite being conceived as genetic female.

As a test, Randy was placed in a cage with some females, with whom he behaved in a typically male-mouse way and mated up to six times a night. "He thought he was male, they thought he was male and we thought that was pretty good evidence," Sinclair says. It tells you that SRY is the only gene you need on the Y chromosome to develop testes and become male.

When a human foetus is still thumbnail-sized, you can't tell a male from a female one - the budding sex tissues are identical.

If it is male, however, SRY switches on about seven weeks after conception and causes testes to form, which soon flood the developing baby's body with the male sex hormone testosterone.

That hormone shapes the development of male genitals and physical traits - larger body size, more muscle, less fat, more body hair and so on.

Without SRY, a female foetus waits until 13 weeks to develop ovaries (from exactly the same tissue buds that produce the male's testes), which produce the female sex hormone oestrogen to feminise its body.

Every significant distinction between men and women seems to stem from the actions of SRY. As Jennifer Graves, a prominent genetics researcher at La Trobe University, Melbourne, puts it: "Of all the differences between male and female mammals, the primary one seems to be the development of the testis in males."

It is often argued that being female is the default state for mammals. It now seems just as possible we start out sexless but with dual potential.

It's worth noting that SRY's discovery was made possible with the help of French scientists who identified four unusual men who had sought treatment for infertility. Tests revealed that all four were in fact genetic females, yet they had men's bodies, including testes.

Further studies showed that an SRY gene had somehow become attached to one of their X chromosomes. It was just a tiny glitch, enough to reverse their sexual anatomy but not to endow them with other male genes needed to make sperm.

Many other such variants are now being discovered - along with true hermaphrodites and pseudo-hermaphrodites, there are people with missing sex chromosomes, extra sex chromosomes, or tiny genetic fragments tacked onto or missing from chromosomes that seem to have nothing to do with sex determination.

The Intersex Society of North America asserts that one person in 500 has sex chromosomes that are neither the usual XX for women or XY for men.

Many such people do not discover this until they seek help with fertility problems. One group is genetically male with a condition known as androgen insensitivity syndrome, or AIS. In essence, their receptors to testosterone don't work.

So, even though they have male chromosomes and the SRY gene intact, their genitals and general body form are not masculinised in the womb. They develop outwardly female bodies but may have internal testes instead of ovaries.

Some grow into women who are taller than average and more square-shouldered, small-breasted and narrow-hipped. As Sinclair points out, these features paradoxically make them potentially attractive as fashion models.

Zoologists have muddied the sex picture further. It is now plain that many degrees of maleness and femaleness exist in nature and that a rainbow of variant hues is possible between the pink and blue.

There are species with six or more gender categories, countless kinds of fish that change sex, males that bear the main burden of parenting, females that seize social power by violent force and a growing tally of at least 200 species (including our nearest relatives, the chimps) in which homosexual activity occurs.

One of the strangest is the angler fish, which has reached a ruthless conclusion to the battle of the sexes. These bizarre animals are famous for lying motionless and camouflaged on the ocean floor while a weird little fleshy protrusion on their heads is dangled and wriggled, like a baited fishing rod, in front of their mouths. Any hungry fish coming too close are soon devoured.

But adult anglerfish are always female and we now know that they have other weird fleshy protrusions to explain why.

It turns out that young male angler fish drift around until they encounter a large female, then latch onto her body. In time, the two literally fuse together, becoming one individual - flesh and blood, Mr David and Mrs Goliath.

His body shrivels away until only the genitals are left, dependent on her for life-support. Sometimes a mature female may sport as many as five or six sets of male genitals, the only function of which is to provide the sperm from which she can fertilise herself.

"As a biologist I see enormous flexibility in living forms and have considerable scepticism about the fundamentalist need to classify male and female with such rigidity," says Jim Cummins, of Murdoch University in Western Australia.

Human culture has shown that it can be flexible about gender ambiguity. Many peoples throughout history have tolerated, accepted or even encouraged ways for individuals to permanently or temporarily change gender.

Societies as diverse as Albania (with its sworn virgin women who dress, live and work as men), Native American nations (with their respected two-spirit people) and Polynesian peoples (with social categories such as the faafafine - men who are like a woman - of Western Samoa) have all found ways to accommodate gender variants.

Traditional gender stereotypes are far from dead, though. Despite much sustained social pressure for change, long-standing male and female social roles are still widely adhered to and prominently on show in public life, from the TV screen to the rugby field.

As Maccoby argues, science has shown us that the basis for being labelled male or female at birth is biological, but the labelling itself is social and it pervades our lives from the start.

That a child should come to understand his or her gender identity at an early age - as well as the gender identities of others - is no surprise, she says. It is an overdetermined matter.

Delving into sexual genetics and chemistry and making personal contact with people of ambiguous sex and gender has made Sinclair see the issue in a fresh light.

"I think humans like things to be ordered and they get bothered about grey areas and when things become less clear-cut," he says. "But these days I don't think so much in black and white about male and female. Now I think of it all as being on a spectrum."