The phrase "nature and nurture" is a convenient jingle of words, for it separates under two distinct heads the innumerable elements of which personality is composed. Nature is all that a man brings with himself into the world; nurture is every influence from without that affects him after his birth. The distinction is clear: the one produces the infant such as it actually is, including its latent faculties of growth of body and mind; the other affords the environment amid which the growth takes place, by which natural tendencies may be strengthened or thwarted, or wholly new ones implanted.
-English Men of Science: Their Nature and Nurture
Francis Galton (1970/1874)
Ever since Sir Francis Galton created one of science's few bone fide sound bites—"nature versus nurture"—the nature-nurture debate has reverberated through the halls of academia. To what extent are important human characteristics innate or learned? Nowhere is this debate more contentious than in the study of gender.
Given that gender is the topic of this book, it is perhaps ironic to start with a quote from Galton, who didn't even deign to include women in his purview ("Nature is all that a man brings with himself into the world..." [italics added]). Although Galton is credited with originating the nature-nurture debate in psychology, he is also sometimes criticized for being sexist and racist. Whatever Galton's ideologies, his words are an appropriate starting point, for they not only set the tone for the nature-nurture debate but also hint at the political and ideological overtones that would come to inflame that debate.
Today, to ask whether there are biological factors that lead to sex differences is not just to pose a scientific question. It is to scrape open old wounds inflicted by sexist ideologies and to confront stubborn prejudices on all sides. Biological theories of gender have been used to belittle and oppress women in the not-so-distant past; thus, it is no wonder that contemporary feminists view such theories with suspicion. Phrases such as "anatomy is destiny" and "heredity is destiny" have served too often as predictions of positive destinies for in-groups (men) and negative destinies for out-groups (women).
Still, no one can doubt that men and women are biological creatures. Although unique in many ways, humans are animals and, like other animals, we have been molded by evolutionary forces that sometimes produce sex differences. We are not just enculturated men and women; we are also embodied men and women. Too often in the study of gender, biological theories have been relegated to the category of politically incorrect or even reactionary.
Unfortunately, partisans on both sides of the nature-nurture debate have too often talked past one another. Sometimes, they have even hurled invectives at one another. So why write a book that places itself (not to mention its author) in the crossfire of such a rancorous debate? One simple answer is that the nature-nurture controversy—whether applied to gender or to other topics—is fascinating. It touches upon a host of important real-life questions. To what extent can parents influence their children's personalities and intellects? What are the limits of educational enrichment? Are geniuses born or made? Is sexual orientation innate, learned, or chosen? Can mental illness be in our genes? Does violence come from bad blood or bad environments?
Like Galton, we want to know how much a person's environment can "strengthen or thwart" preexisting tendencies. Is it possible to imagine a society, for example, in which women commit more murders than men? Or one in which women like to watch football on TV more than men do? Like Galton, we wonder whether the proper environment can "implant wholly new tendencies" in people. Could we rear a generation of women who are as interested as men in being engineers, or a generation of boys who play with babydolls as much as girls do?
One thing is clear. Over a century of research on the nature-nurture question has produced an explosion of new methods and findings. Were Galton alive today, he would be amazed by the complex mathematical techniques and huge database of modern behavioral genetics, despite the fact that he was the originator of the twin method in psychology. Galton would likely be overwhelmed by advances in biological psychology, neuroscience, and molecular genetics. He might even find himself modifying some of his strong hereditarian beliefs after examining a century's worth of social scientific research.
Today, to understand the nature and nurture of gender we must look to a multitude of disciplines: molecular and behavioral genetics, evolutionary biology, endocrinology, neuroanatomy, ethology, anthropology, sociology, and many branches of psychology. But before we can sift through all of the data, we must first pose a preliminary and deceptively simple question: What is it that we are trying to explain? That is, what is gender? This question forms the central topic of Chapters 1 and 2 of this book. Chapter 1 ("What's the Difference Anyway?") summarizes scientific findings on sex differences in people's behavior and traits. Chapter 2 ("Masculinity and Femininity: Gender Within Gender") summarizes research on gender-related individual differences within each sex. Chapter 3 ("Theories of Gender") presents prominent theories that have attempted to explain these two sides of gender.
Chapters 4 and 5 present research evidence on the nature and nurture of gender. Chapter 4 ("The Case for Nature") argues strongly for the power of biological evolution, genes, hormones, and neural structures to produce sex differences in behavior and gender-related individual differences within the sexes. Chapter 5 ("The Case for Nurture") argues just as strongly for the power of culture, social roles, social learning, stereotypes, and social settings to produce the very same phenomena. Chapter 6 ("Cross-Examinations") presents an imagined debate between a personified Nature and Nurture. Each side attempts to pick apart the other side's case and to sow seeds of doubt in the reader's mind about both strong nature and nurture accounts of gender.
The final chapter ("Gender, Nature, and Nurture: Looking to the Future") strives for a theoretical synthesis, and it examines how the nature-nurture debate touches upon real-life public policy questions. Offering a cascade model of gender, Chapter 7 proposes that biological and social factors trace an interdependent causal cycle over the course of an individual's life and that gender is a phenomenon that can be explained only from a developmental perspective. From the vantage point of Chapter 7, nature and nurture form the inseparable yin and yang of gender development.
Chapter 7 next applies the cascade model to broader public policy questions. Should parents rear boys and girls the same? Is same-sex education beneficial or harmful? Should employers offer men and women the same parental benefits? Should judges in child custody cases treat mothers and fathers alike? Are men and women biologically destined to experience conflicts in their intimate relationships? Do biological or social factors lead to male sexual violence and coercion? Why do men still earn more, on average, than women do, and should society intervene to eliminate the disparity? Why do men hold elective office more than women do, and do women bring new leadership styles to government and business? Should the military treat men and women alike?
None of these questions is trivial. Some will require a Solomon-like wisdom to resolve. Research on the nature and nurture of gender can help us frame these questions more precisely and, perhaps, to answer them more wisely. More broadly, research can help us to understand better the nature of each sex and to nurture that which is admirable in both.