Genes in control: Conservatism in popular science

Lesley J. Rogers, University of New England

D. Bainbridge How the X Chromosome Controls Our Lives Cambridge, Harvard University Press, 2003 (224 pp). ISBN 0-67401-028-0 (hard cover) RRP $46.74.

S. Baron-Cohen The Essential Difference: Men, Women and the Extreme Male Brain London, Allen Lane, 2003 (288 pp). ISBN 0-71399-671-4 (hard cover) RRP $39.95.

R.W. Connell Gender Cambridge, Polity Press, 2002 (184 pp). ISBN 0-74562-716-1 (paperback) RRP $32.95.

Genetic explanations for complex human behaviour are growing in popularity, aided by recent advances in molecular genetics and the Human Genome Project. However, their popularity far exceeds their scientific validity. Books written for a general audience to promote genetic causes for differences in behaviour between men and women are not merely over-simplistic and inaccurate; they also promote particularly conservative opinions about society.

Recent books by David Bainbridge and Simon Baron-Cohen exemplify this kind of popularising of science. Both books hold firmly to the idea that the X and Y chromosomes determine sex differences in anatomy, physiology, and behaviour. In my opinion, neither book stands up well to scientific scrutiny. The development of sex/gender differences—and for that matter their similarities—does involve the X and Y chromosomes but they are not, as Bainbridge and Cohen suggest, the arbiters or the ultimate guides of this process. Rather, sex chromosomes are one aspect of a complex process of development involving experience of the individual within society. It is apparent that neither author understands the complexity of processes of development nor the broader social aspects of gender.

As Robert Connell puts it clearly in his far more enlightened book, ‘Gender is, above all, a matter of the social relations within which individual and groups act’ (p. 9). For Connell, gender is neither an expression of biology, nor a fixed difference. Moreover, it involves ‘massive hierarchies of power among men—as seen in multinational corporations, or armies—which can in no sense be reduced to “male/female differences”, however caused’ (p. 9). From this perspective we can see the short sightedness, if not the blundering mistakes, of the other two authors.

Baron-Cohen believes that there are ‘essential differences’ between men and women, differences determined by genes. Gisela Kaplan and I argue in our recent book Gene Worship that belief in essential differences is an ideological position taken by those claiming genetic causes for human behaviour. We argue that this reductionist thinking needs to be replaced by recognition of the complex dynamics between genes and environmental influences on development. This recognition needs to encompass both analysis at the cellular level and analysis of gender as a social structure (the latter being explained by Connell in his book). It is the interaction of all of these influencing factors that scientists and social scientists should be trying to understand, rather than providing glib and simplistic explanations that maintain inequalities.

Belief in essential sex differences is an ideological position taken by those who claim genetic causes for human behaviour.

To give just one example of the complex interactive processes that take place during the development of sex differences, let me summarise some research findings about this process in rats. I choose to discuss this species because it has been the main model for investigating the genetic and hormonal aspects of sex differentiation. Researchers commonly consider only the genetic and hormonal influences in this process: XY rats produce the sex hormone testosterone, which acts on the brain during the first five days after birth to channel it to develop in a male direction, whereas XX rats lack this hormone and develop a female brain. However, it is far from this simple. Experience in early life also has a marked influence on the development of a male or female brain. Mother rats treat their male and female pups differently: they lick the anogenital region of male pups more than they lick the same region of female pups, because they are attracted to a secretion in the urine of those pups with higher levels of testosterone. Experiments show that this maternal licking affects brain development. If the mother is unable to smell the urine of her pups, because she has small tubes inserted in her nostrils, she licks the XX and XY pups to the same extent and no sex differences in behaviour develop. Moreover, if the anogenital region of genetically and hormonally female pups is stimulated artificially with a paintbrush, the pups develop male-typical behaviour. Hence, the experience of being licked interacts with the genetic and hormonal factors. In other words, without the mother’s input, the rats would not develop sex differences in behaviour despite their genes and hormones. We also know that to behave in certain ways affects the secretion of sex hormones and this adds another layer of complexity to the interactive events that take place during development.

To Baron-Cohen, the female brain is ‘predominantly hard-wired for empathy’ and the male brain ‘hard-wired for understanding and building systems’ (p. 1). Bainbridge too believes in the existence of a gene on the X chromosome that gives girls extra social skills, and those girls who lack it become socially disruptive—watch out feminists! According to Baron-Cohen’s theory, women have an empathising brain (type E), shown in baby girls as a preference for looking at a model of a human face over a mobile and in later life as a preference for reading magazines on fashion, romance, intimacy, and beauty, and spending their time on coffee mornings, as well as caring for people and pets. The ability of women to empathise, Baron-Cohen suggests, may lead to better language skills because females pay more attention to listening to others and in communicating well. Men, he says, are more likely to have a systemising brain (type S) that directs their attention, as babies, to the mobile instead of the face, and later to magazines about computers, cars, boats, science, and consumer guides. Further, because they like to follow sets of rules, type S men are more likely to practise plane or bird spotting and photography. In the wider arena, a type S is likely to be a leader of some sort (perhaps a politician or a scientist), whereas a type E is likely to be a nurse, teacher, or homemaker.

Baron-Cohen’s descriptions of what he sees as sex-typical behaviour clearly aim at reinforcing traditionally held divisions between the sexes. However, as Connell says, these apparent differences between men and women are beliefs rather than facts. These beliefs have often been the starting point for empirical research and, as I have discussed in more detail in my book Sexing the Brain, they often blind scientists when they interpret their results. This bias leads to research flawed by poor controls, with results incorrectly interpreted to reinforce the scientists’ belief in difference.

Baron-Cohen begins his book by attempting to convince us that he is being courageous in putting forward his ‘new’ theory, claiming that the topic of innate sex differences has been taboo for some time. My first response to this is that I see nothing new in his ideas. It is not difficult to see that his idea about the female predisposition to empathise differs little from the long-asserted claim that female nurturing behaviour is innate. As Connell says, women are supposed to be nurturing, suggestible, talkative, emotional, intuitive, and sexually loyal, whereas men are supposed to be aggressive, tough-minded, taciturn, rational, analytic, and promiscuous. For many years, biologists, especially sociobiologists and evolutionary psychologists, have been trying to convince us that these traits are genetically determined. Baron-Cohen is but one of the many—the history of using biology to keep women in second place dates back to Aristotle. These conservative, if not plainly oppressive, views have always had a voice, despite Baron-Cohen’s protestations. Even during the 1970s and 1980s, when we hoped that women would gain equality, traditionalist views were published (and, sadly, often expressed by women scientists as well, as they still are today—by Doreen Kimura (1999), for example). In fact, biologists other than those purporting genetic causation of so-called essential differences between women and men have found it difficult to make themselves heard. In other words, Baron-Cohen is not amongst a minority of thinkers and researchers prepared to speak the ‘truth’ to, in their opinion, the misguided politically correct.

Baron-Cohen is not amongst a minority of thinkers and researchers prepared to speak the ‘truth’.

Next Baron-Cohen tries to convince us that he is not repeating ‘old forms of oppression in a new guise’ (p. 10) but this posturing does not convince me, and I am sure, or hope, that it will not convince the majority of readers. Baron-Cohen tries to convince us that he wants to avoid further oppression of women by saying that the type E and type S refer to mean differences between the sexes and that there is substantial overlap between them. However, you cannot say that a sex difference is ‘hard-wired’ on the one hand and then try to wriggle out of this clear statement of genetic causation by saying that you are dealing with mean differences and not absolutes. As Americans would say, ‘Who is he trying to fool?’ What needs to be questioned is what is really being measured, how accurate are the measurements, how large are the average differences and do they have any meaning in everyday life?

Even more questionable are the assertions, made not only by Baron-Cohen but also by a growing band of evolutionary psychologists, that selection for these hypothesised genetic differences took place in ancestral humans. There is no convincing evidence that social roles of ancestral men and women differed in ways that would have favoured enhanced type S brains in males and type E brains in females. Even if ancestral men were doing the hunting for food while women stayed in the camp—and this too can be questioned—one could imagine that group hunting required communication and empathy (type E) and that preparing food for cooking was systematic (type S). Of course, one could argue the opposite and, in fact, either argument is so lacking in supporting evidence that the claims made by Baron-Cohen and other evolutionary psychologists are totally unconvincing.

However, the existence of any average difference between the sexes tells us nothing about what causes the difference. In my opinion, this is the interesting and most important question that scientists need to address. Scientists need to set aside prejudice and unitary, simplistic explanations to make a concerted effort to understand the complexities of development and how experience impinges on genetic expression. There is plenty of scientific evidence showing the complex interactive, and ever-changing, influences of experience and genes on how organisms develop. It is this evidence with which we need to work. I fail to see how we can deepen our understanding of the functions of a host of contributing factors by focussing on control by the genes. Moreover, scientists interested in this topic should familiarise themselves with the sociology and psychology of difference before embarking on this path. This will ensure they are harbingers of social change rather than apologists for the status quo. Then, and only then, will we see science as discovery at work.

Meanwhile, books like those of Bainbridge and Baron-Cohen will be widely promoted by the media because simple, reductionist explanations have a popular appeal, especially in today’s increasingly conservative climate. Books like Connell’s, which is one of the few against the tide of genetic explanations of human behaviour, will hold on to our hopes for a more egalitarian society in which science can be practised without being propaganda.

The existence of any average difference between the sexes tells us nothing about what causes the difference.

Finally, I would like to make a point about writing style. I am strongly in favour of communicating science to a wide audience, and this demands skills quite outside the range needed to communicate within one’s scientific field. However, I am very concerned about the success of a recent trend to capture attention by turning science into a mock mystery story and by reducing the complexity of explanations. Apparently, one way to inject excitement into what otherwise might have been a rather dry story is to give things and processes personalities. Richard Dawkins achieved much fame by adopting this approach in his book, The Selfish Gene, and Bainbridge joins a rather long line of his followers. How the X Chromosome Controls Our Lives attributes personality to the X-chromosome. Dawkins gave the genes selfish personalities because, according to his theory, their drive to replicate determines every aspect of our behaviour. Bainbridge gives the X and Y chromosomes personalities to enliven his subject matter. Both approaches are reductionist: they reduce complex behaviour to the working of a set of genes, and ignore the layers of explanation in between, with all of their complexities.

Bainbridge describes cell division as an ‘especially elaborate chromosomal dance’ (p. 5), a dance in which the X chromosome does not take part. Choosing not to ‘take part in the festivities’ the ‘wallflower chromosome’ (that is, the X chromosome) is seen as an ‘extra’ (p. 5), later referred to as the ‘antisocial X chromosome’ (p. 10) and then as ‘our dictator’ (p. 62) and as a ‘hotbed of sex-related genes’ (p. 123). By contrast, the Y chromosome is said to be a ‘king’ (p. 17). It does not take much imagination to see the author’s social attitudes revealed by these terms. They are further revealed when he describes the dominant role of the Y chromosome in determining the male (and by implication maleness), whereas being female is a default position resulting from the absence of a Y chromosome: the following passage makes Bainbridge’s sexism absolutely clear:

Male superiority is an ancient fortress, but it has somehow become situated on the new scientific frontier. In a world where men have lost their old birthright, where their confidence has been eroded by women’s success in so many aspects of life they once considered their own, is the way in which sex is allocated the last and only true scrap of male supremacy? Female-as-default is a challenging idea because it is politically incorrect but scientifically incontrovertible, at least superficially (pp. 31–32).

It is superficial indeed! Clearly, the metaphors chosen by Bainbridge to describe the biology of sex differences uphold belief in male superiority.


Dawkins, R. 1976, The Selfish Gene, Oxford University Press, Oxford.

Kimura, D. 1999, Sex and Cognition, MIT Press, Cambridge, MA.

Kaplan, G. and Rogers, L. J. 2003, Gene Worship: Moving Beyond the Nature/Nurture Debate Over Genes, Brain, and Gender, Other Press, New York.

Rogers, L. J. 2000, Sexing the Brain, Columbia University Press, New York.

Lesley J. Rogers is Professor of Neuroscience and Animal Behaviour at the University of New England.