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| Acknowledgments | ix | ||||
| Prologue: Beginnings | xi | ||||
| PART ONE: HUMAN NATURE | 1 | (72) | |||
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3 | (21) | |||
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3 | (3) | |||
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6 | (5) | |||
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11 | (4) | |||
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15 | (4) | |||
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19 | (3) | |||
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22 | (2) | |||
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24 | (17) | |||
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24 | (1) | |||
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25 | (2) | |||
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27 | (2) | |||
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29 | (4) | |||
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33 | (2) | |||
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35 | (3) | |||
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38 | (3) | |||
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41 | (32) | |||
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41 | (2) | |||
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43 | (8) | |||
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51 | (7) | |||
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58 | (7) | |||
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65 | (8) | |||
| PART TWO: SOCIAL LIFE | 73 | (80) | |||
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75 | (20) | |||
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75 | (1) | |||
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76 | (5) | |||
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81 | (6) | |||
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87 | (6) | |||
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93 | (2) | |||
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95 | (30) | |||
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95 | (4) | |||
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99 | (4) | |||
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103 | (3) | |||
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106 | (6) | |||
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112 | (4) | |||
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116 | (5) | |||
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121 | (4) | |||
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125 | (28) | |||
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125 | (3) | |||
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128 | (3) | |||
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131 | (7) | |||
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138 | (2) | |||
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140 | (1) | |||
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141 | (5) | |||
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146 | (4) | |||
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150 | (3) | |||
| PART THREE: CIVILIZATION | 153 | (60) | |||
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155 | (19) | |||
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155 | (1) | |||
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156 | (5) | |||
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161 | (2) | |||
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163 | (2) | |||
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165 | (1) | |||
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166 | (6) | |||
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172 | (2) | |||
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174 | (20) | |||
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174 | (2) | |||
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176 | (6) | |||
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182 | (3) | |||
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185 | (2) | |||
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187 | (3) | |||
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190 | (2) | |||
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192 | (2) | |||
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194 | (19) | |||
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194 | (1) | |||
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194 | (2) | |||
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196 | (3) | |||
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199 | (3) | |||
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202 | (1) | |||
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202 | (5) | |||
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207 | (2) | |||
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209 | (4) | |||
| Epilogue: The Circle | 213 | (4) | |||
| Notes | 217 | (30) | |||
| References | 247 | (22) | |||
| Index | 269 |
The New copy of this book will include any supplemental materials advertised. Please check the title of the book to determine if it should include any access cards, study guides, lab manuals, CDs, etc.
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Chapter One
The Animal Within
RASCALS, HEROES, AND COLORFUL PEOPLE
Sylvia Cross pushed her piano out into McLendon Avenue, smashed it apart with a hammer, and distributed the pieces among her friends who'd stayed for the grand finale of the last all-night party at Sylvia's Atomic Café. Business had been slow because a sinkhole had closed the street. Sylvia was bored and ready for a career change. She decided to go into art. She bought another piano and opened a new store, Sylvia's Art of This Century, an art supply boutique with musical entertainment in the evening. The last time I saw Sylvia, she was ready for another career change. She was planning to go on the Internet as an erotic storyteller.
Sylvia has a high-testosterone approach to life. She is a showperson and entrepreneur, and she deals with problems directly and flamboyantly. A few years ago she wanted to buy a house but didn't have money for the down payment. She solved the problem by having parties and selling tickets to her friends. Parties come naturally to Sylvia, and before the sinkhole, Sylvia's Atomic Café was an ongoing party in northeast Atlanta. It featured informal entertainment, often provided by Sylvia herself. One of the tricks she performed was fire-eating, which she'd learned from a circus performer.
While Sylvia was still in the restaurant business, a friend of mine who was a friend of hers told me Sylvia would make a good subject for the testosterone research I was doing. Sylvia told my friend she would be glad to participate if I let her know the results. When the lab finished her assay, I marked her score on a graph along with the scores of a group of college women and a group of violent women from the local counterculture. Sylvia was higher in testosterone than the college students and right in the middle of the violent group. My friend took the graph to Sylvia at the café. Sylvia was delighted. She passed the graph around among her customers, telling them that her testosterone level was as high as that of most skinheads and devil worshipers. Sylvia seemed to think a high testosterone level was an asset, and in this her opinion was absolutely mid-American. My research assistants and I have found that almost everyone--men, women, high school dropouts, college graduates, reporters, prisoners, and stockbrokers--wants to have a lot of testosterone.
Construction workers are no exception. As a group, they do have more testosterone than average, and they are proud of it. One of my former lab assistants, Denise de La Rue, had a friend, Mike Roseberry, who was a construction supervisor. Mike agreed to ask his work crew to provide saliva samples to be assayed for our testosterone study. They were enthusiastic about what they called the "Testosterone Olympics." They wanted to know their scores. I made a graph showing all the scores, but without saying who scored what. Intending to preserve their privacy. I sent them their individual scores in sealed envelopes. They were not interested in privacy; they were interested in competition. Pretty soon everyone knew everyone else's score, and as would be expected, because testosterone levels fall with age, one of the older men had the lowest score. The others immediately gave him a girl's nickname. Mike, like Sylvia, was pleased with his score. He called Denise and left a message, "Hey, Denise! I spit a ten. Not everybody can spit a ten."
The stereotype of a construction worker is muscular, tough, and sexy. Mike does not question the stereotype. Although many women give wide berth to construction sites, Mike doesn't see those women. He sees the ones who stop by and leave their telephone numbers with the men. Perhaps there is a difference in testosterone levels between women who do and do not find construction workers attractive.
A few years ago, while I was studying construction workers and testosterone, a living example of the stereotype appeared on the Geraldo show. He was lean, muscular, bald, bearded, and tattooed. His friends called him "Animal." With him were his ex-wife, his live-in girlfriend Michelle, and two of his eight other girlfriends. Michelle, who was wearing a short skirt and white cowgirl boots, had met him at a construction site. She had a tooth missing from a fight with Animal, but she said she had injured him in the same fight as well, and neither of them seemed to be holding a grudge about it. She had one child who they agreed was his, but there was some animosity between them about who the father of her other child might be. She said it was Animal; he said it was somebody else. Another point of conflict between Animal and Michelle was Animal's ex-wife, whom he continued to visit each week. Michelle and the ex-wife did not like each other, but otherwise the various women got along well and were happy to share Animal. No one in the group was talkative, though they all answered questions when asked. My first thought was that Animal, and maybe his girlfriends, were suffering from what Alan Alda once called "testosterone poisoning," but on television they made a mostly peaceful scene.
Sylvia, Mike, and Animal, like many people who are high in testosterone, are confident, tough, competitive, bold, energetic, attractive to the opposite sex, and they are frequently outrageous. They have characteristics in common with James Bond, Kinsey Millhone, Night Man, Buffy the Vampire Slayer, Indiana Jones, Luke Skywalker, Sam Spade, and Xena the Warrior Princess. Fictional heroes and heroines let us experience life in dangerous times and on the risky edge of society. Every once in a while, a real macho hero makes the headlines and lifts the spirits of everyone. In the spring of 1999, Matt Moseley put good news on the front page. Moseley was the Atlanta fireman who, dangling from a helicopter line, rescued a crane operator trapped above a burning building. Then, two months later, a team of American women soccer players won the 1999 Women's World Cup and put good news on the front page again. Brandi Chastain kicked the winning goal and flexed her muscles on the cover of Newsweek , and Women's Cup madness was in.
Most people have at least a vague idea about what testosterone is, and in spite of talk about "testosterone poisoning," they believe it is a good thing. When we ask people what testosterone is, they are likely to describe it in terms of football, the Marines, fighting, hunting, fishing, carburetors, tall tales, and sexual adventures. Sometimes they say, "You know, it's guystuff."
"Guystuff" is just part of the testosterone profile. Researchers have been busy adding new details to what is turning out to be a complex and intriguing picture. My students and I have found that whenever our work is mentioned in newspapers or magazines, we hear from people who think their testosterone is high and want verification from an expert, or who think it is low and want to know how to increase it. I get calls from people who want their testosterone measured. Not all the calls come from men. Quite a few women--an opera singer in Connecticut, a business entrepreneur in Texas, a telephone sex operator in Chicago, and lawyers in San Francisco, Washington, and New York--have called me.
Over the years, students approached me to study testosterone in lawyers, testosterone and violence in lesbian couples, testosterone and sexual intercourse, testosterone and the counterculture, and testosterone among fans at sporting events. Our research meetings took on a storytelling atmosphere, as students outdid each other in bringing new findings. We studied people ranging from ordinary to truly strange, and we began to uncover many links between testosterone and social behavior.
People who exhibit the qualities linked to testosterone are as varied as Bay and Pat Buchanan, O. J. Simpson, David Koresh, Madonna, Governor Jesse Ventura, Monica Lewinsky, Phyllis Schlafley, Eric Rudolph, George Steinbrenner, Clarence Thomas, and many members of the Kennedy family. Whether they are rogues or heroes, they are colorful people, and their exploits, escapades, and even their nefarious deeds capture our attention and fascinate us.
MEASURING TESTOSTERONE
In order to learn about testosterone, and to separate it from social, cultural and other biological influences, we had to measure it in a large number of people. We needed a measure that was simple, painless, and reliable. The standard technique for measuring testosterone is called radioimmunoassay, or RIA. Until recently, RIA measured testosterone only in blood. That limitation was a roadblock to researchers who needed a large number of samples from the general population. People balk at volunteering their blood for science.
Fortunately, I learned that RIA could also measure testosterone in saliva. Saliva is a good substitute for blood as a diagnostic fluid. Saliva originates in a network of blood vessels near the salivary glands, and testosterone passes from the blood into the saliva. Measurements of testosterone from saliva are as reliable as measurements from blood. Further, when we tried collecting saliva samples, we found that large numbers of people would volunteer for our studies. Occasionally we did have to reassure them that we were looking only for testosterone, because saliva tests can also indicate whether a person has been using alcohol, tobacco, or drugs.
Using salivary measures, my students and I set up procedures and began collecting data. Over the years we analyzed saliva samples from more than three thousand college students, prison inmates, trial lawyers, athletes, heroes, construction workers, sex offenders, strippers, actors, wrestlers, and various others. We measured people several times each, to examine changes across the day and around important events. We also examined data on blood levels of testosterone from government records of about five thousand military veterans.
People often ask me what a high testosterone score is. When Mike Roseberry said he'd "spit a ten," that meant the concentration of testosterone in his saliva sample measured ten nanograms (ng) of testosterone per deciliter (dl) of saliva. That was a high score in his particular assay batch. In our lab, we run assays in batches that range from thirty to fifty samples each. In another lab run, Mike's score might have been a little different, but still high in his particular assay. Radioimmunoassays often take two days to complete, and there is normal analytic variability in every lab that performs them. Variability in results from assay to assay are due to slight differences in chemicals, procedures, and lab personnel. Because of this variation, we include a high control and a low control sample in each assay. The comparison with known values tells us more about the testosterone level of a particular individual than his or her "number." That is why when I describe individuals, I say they are "high," "medium," or "low," rather than they scored a "two," "six," or "ten." Scores from blood samples are about a hundred times higher than scores from saliva samples, but the numbers are highly correlated with each other, which means that one measure is as accurate as the other.
Although testosterone is not visible to the naked eye, and there is no single marker to reveal its presence, we learned during the course of our research that testosterone is related to traits that are readily observed. For example, high-testosterone men, on average, are leaner, balder, more self-confident, more rambunctious, less likely to have friendly smiles, and more likely to favor tattoos than other men. That is not to say that we can look at a particular individual and know with certainty what his or her testosterone level is. Many characteristics and behaviors that are related to high testosterone levels are also related to social, cultural, and other biological factors. Nevertheless, my students who are familiar with testosterone research can often look at pictures of experimental subjects and tell which subjects are high or low in testosterone. As my students and I become more familiar with what high- and low-testosterone people are like, we get better at predicting which research projects will be productive.
Testosterone is a hormone, and understanding it requires a general understanding of hormones and how they work. Hormones are molecules, tightly bound clusters of atoms, that carry messages from one part of the body to another. Hormone molecules can be small, because all they do is carry simple messages, but they must be numerous enough to spread throughout the body. Each person, man or woman, produces just a few milligrams of testosterone every day, but each milligram contains a million trillion molecules.
Endocrinologists, who study hormones, group hormones into families, in which members of the same family have similar origins and do similar jobs. For example, in the brain there is a family of hormones called endorphins that spreads feelings of pleasure and blocks feelings of pain. Elsewhere in the body there are families of hormones that control growth, metabolism, storage of energy from food, and release of stored energy in emergencies. Testosterone and estrogen are the major players in the sex hormone family They start off as cholesterol, one of the building blocks of the body. Cholesterol is converted into testosterone by the action of enzymes, substances that change molecules from one form to another. This conversion takes place in the testes, ovaries, and adrenal glands. Testosterone can then be converted into a more potent form called dihydrotestosterone by the enzyme 5-alpha-reductase, or into estrogen by the enzyme aromatase (so named because its products sometimes have an "aroma" like that of benzine). Testosterone can be converted into estrogen, but estrogen cannot be converted back into testosterone. It is an oddity of sex hormones that estrogen in males and females comes from testosterone. Both sexes have testosterone and estrogen, although men have more testosterone and women have more estrogen. The same individual can have high levels of both hormones. Stallions have high levels of estrogen and testosterone, as do football players and rattlesnakes.
Figure 1.1 shows the molecular structure of testosterone and estrogen. Testosterone molecules have twenty-one carbon and oxygen atoms. Removing one carbon atom changes testosterone into estrogen. The similarity of the two hormones is perhaps a metaphor for the similarity of men and women. Men and women are similar in many ways--in their bodies, their minds, their hopes and fears. We should remember this underlying similarity when thinking about the ways in which they differ.
Hormones operate by moving through the bloodstream from cells that produce them to target cells. When they reach the target cells they fit into receptor molecules, like keys into locks. What happens next depends on what the cells are designed to do. Cells are diverse, ranging from those that make up the brain to those that are parts of muscles, toenails, and eyelashes. In the nucleus of each cell, genetic material in the form of chromosomes--double strands of long DNA molecules--tells the cell what to do. Genes are sections on the DNA strands, and they contain information needed to build and maintain the body. Each cell has a complete set of genes, but it uses only a few of them. When a cell uses a gene, we say it "expresses" that gene. Gene expression begins when part of the double-stranded DNA unravels into a single strand, called RNA. The RNA moves out of the nucleus and into the main body of the cell, where it attracts small building-block molecules to form stable groups that make up new protein molecules. Creating the new protein is a step toward meeting the need of the moment, whether that need is to digest a meal, add a bit of muscle, attract a lover, or prepare for a fight.
Testosterone has many functions. Among other things, it signals cells to build muscle, make red blood cells, produce sperm, and release neurotransmitters in the brain. A testosterone molecule acts upon its target cell in one of two ways. It binds with a receptor at the membrane surrounding the cell and triggers action there, or it passes through the membrane to bind with a receptor inside the cell and triggers the expression of a gene. Action at the membrane can be completed within seconds. Action inside the cell takes minutes or hours. Action inside the cell is complicated by the fact that testosterone, after binding with a testosterone receptor, is often transformed into estrogen (by aromatase) before triggering gene expression. Thus we have the interesting situation in which men, whose primary sex hormone is testosterone, convert their testosterone into estrogen before using it.
Testosterone is a sex hormone, and I think it is the most social of hormones. Other hormones indirectly affect the brain and mental function by affecting other organs of the body first. Testosterone makes direct contact with many cells in the brain. It stimulates activity in those cells, and that activity goes on to affect thinking. The major social effect of testosterone is to orient us toward issues of sex and power. This provides a background against which we act, encouraging some behaviors and discouraging others. It affects how we treat other people and how we react to the way they treat us. It makes Us impatient with dull and boring aspects of school, but if we manage to sit through school and listen to our elders, the lessons we learn restrain and guide the effects of testosterone.
Testosterone has two different, but coordinated, effects on the mind and body. It is involved in both design and function. It first helps organize and develop the body and brain, beginning before birth and continuing through adolescence. It then helps direct activities in the body and brain throughout life. It is like a young automotive engineer who designs a fast, powerful car and then races it. The engineer designs a car with the capacity for power and speed, and then later he uses that capacity to race. Testosterone designs a fetus with the potential for power and speed, and when the fetus grows into an adult, testosterone encourages the adult to use this potential.
THE FETUS
Testosterone first appears in utero , where its job is to turn a neutral fetus into a male. Sex is determined by the X and Y chromosomes; females have two X's and males have an X and a Y. There is one gene, lying along the Y chromosome of every male, that determines his development as a male. The presence of this gene, like the flip of a switch, sets the stage for all that follows. The fetus starts off as a single cell, without a brain or body Testosterone appears in the middle third of pregnancy, and it transforms the developing fetus into a male. When the gonads first appear, they are undifferentiated--neither ovaries nor testes. Left alone, they will become ovaries. Fallopian tubes will grow out of ducts in their sides, and a female reproductive system will grow out of the fallopian tubes. If the fetus is to be male, however, the gene on the Y chromosome will act to close these ducts and develop cells that produce testosterone and later produce sperm. Males and females are built from the same basic body parts. Organs that appear to be found only in one sex are in fact present in rudimentary or modified form in the other sex. Thus, in females, the gonads remain inside the body and develop into ovaries, and in males, they descend below the body and develop into testes. Dihydrotestosterone, a potent form of testosterone, causes external genitalia in males to develop into a penis and scrotum. Otherwise the same organs develop into a clitoris and the folds around the vagina in females.
Testosterone goes beyond determining the difference between males and females. The amount of testosterone affects the degree of masculinity within each sex. Regardless of whether people are male or female, they vary in how masculine they are. There are many examples, from animals and people, of how testosterone increases masculinity. Female hyenas are tougher than males because testosterone from their mothers affects them as fetuses. Canary mothers put a little extra testosterone into the last few eggs they lay in each clutch. All the eggs hatch at the same time, and testosterone gives chicks from the last few eggs an extra toughness to compete with their "older" brothers and sisters.
Hormonelike substances from the environment can sometimes affect the fetus. In the 1950s and 1960s, physicians prescribed diethylstilbestrol, or DES, to prevent miscarriages. DES is a synthetic estrogenlike hormone, but in utero it has some testosteronelike effects. The daughters of women who took DES were more masculine than other girls. They played with boys' toys and engaged in more rough-and-tumble "tomboyish" play. My wife's cousin took DES when she was pregnant, and she had a hyperactive, hard-to-handle baby girl, who grew up to be a supersalesperson in the cellular phone business. Unfortunately, the DES also caused reproductive disorders in many of the children of mothers who took it.
Pregnant women no longer take DES by prescription, but they can get it and similar chemicals from the environment. These chemicals are called "estrogenic," because they work like estrogen. Farmers give DES to cattle to promote growth, and some is passed on to people who eat meat from the cattle. A pregnant woman who encounters these substances can pass them on through her bloodstream to the fetus she is carrying. Later on, she can pass them on to her infant through her milk. Among some reptiles, birds, and fish, environmental pesticides and pollutants can feminize males. In 1980, there was a large pesticide spill in Florida's Lake Apopka. Following the spill, zoologists examined young male alligators from the lake and found they had low testosterone levels, high estrogen levels, and exceptionally small penises.
Testosterone from human mothers affects their offspring. A recent study examined the daughters of mothers who were low or high in testosterone. High-testosterone mothers tended to have high-testosterone daughters, and when the daughters grew up they were more masculine in their manner. Because testosterone exerts many of its effects after it is converted into estrogen, one might expect that estrogen from the mother would also masculinize the fetus. This does not happen, perhaps because female fetuses are protected by a substance called alpha-fetoprotein, which blocks the potential masculinizing effect of the mother's estrogen.
Testosterone that influences the fetus can come from another fetus sharing the same pregnancy. Among people, girls with boy cotwins are more tomboyish than girls with girl co-twins. This is partly due to the girls' experiences of growing up with twin brothers, but it is also biological. I once had a bold and forward female student assistant, an expert softball pitcher who married a football player, wanted to learn to box, and enjoyed going to prisons with me to collect testosterone measurements from inmates. She told me she was different from her sisters, who were more feminine, and she wondered why. When I told her about twin brothers, her mouth fell open. She said she had a twin brother who died at birth. He had not been around to affect her while she was growing up, but his testosterone could have affected her before she was born. We measured her testosterone level, and it was above the female average. When they share the womb with male siblings, females can get enough extra prenatal testosterone to masculinize them to varying degrees. The extra prenatal testosterone can increase the number of their testosterone receptors and make them more sensitive to testosterone in later life.
Testosterone from one fetus affecting another in utero has been studied more in animals than in people. Farmers have long known that when a cow has male and female twin calves, the female will be sterile. Such a calf is called a "freemartin," and the effect is presumably due to the testosterone she gets from her cotwin. In other animals, females born with males are not sterile, but testosterone from the males still affects them. During gestation, gerbil fetuses are lined up in the uterus in a row, like peas in a pod. A female gerbil situated between two males in the uterus will grow up to be more masculine than one between two females, and she will have more male offspring. Among human beings, women who are more dominant are reported to have more sons. How this could happen is unclear, because it is the father's sperm rather than the mother's egg that determines whether conception will produce a male or a female. However, genetic factors or local chemical and physiological factors might affect a woman's reproductive tract so as to affect differentially the viability of x- and y-bearing sperm before conception, or the viability of male and female zygotes after conception. The human studies have not measured the mothers' testosterone levels, though I suspect more dominant mothers are higher in testosterone. Some informal studies suggest that this may be the case.
A student at Georgia State University, Jonathan Bassett, has been exploring this area. Research shows that testosterone differs among occupations, so Jonathan used occupation as an indicator of testosterone level, in lieu of actually measuring it. He thought that women trial lawyers, known to be a high-testosterone group, would have more sons than daughters. He read the biographical sketches of the women trial lawyers listed in Who's Who and found that 58 percent of their children were boys. Findings from waist-to-hip-ratio research suggested to Jonathan that curvaceous figures might be correlated with lower testosterone levels and thus that beauty queens, generally a curvaceous bunch, might be significantly different from trial lawyers in the sex ratio of their children. He read the biographical sketches posted at the Miss America Internet site, www.missamerica.com, to see if former Miss Americas had more daughters than sons. They did. They had twice as many.
Extra , a syndicated television magazine show, ran a story about Jonathan's findings. Extra did some research, too. They thought the women working in the high-pressure atmosphere of the newsroom at Extra would be high in testosterone and, if Jonathan's hypothesis was right, they would have more boys than gifts. Of the eleven women who had children, eight had boys, and three had girls.
Researchers have paid more attention to how testosterone affects babies in utero , but there is some research concerning the effect of testosterone from the fetus on the pregnant mother. Gene Sackett, who studies monkeys, found that other monkeys bit pregnant monkeys less often when the pregnant monkeys were carrying males than when they were carrying females. Sackett suspects that hormones from the male fetus passed into the bloodstream of the mother and led her to behave in a more masculine manner, which in turn made the other monkeys more cautious about biting her. Researchers have not studied how the sex of the fetus might affect a human mother, but some women report anecdotally that they can feel a difference emotionally between carrying a boy or a girl.
(Continues...)
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