How science defeats scientists: Darwin believed that men are superior to women, but evolution does not

To prove the inferiority of women,

Anti-feminists not only began to act like

As in the past, we resorted to religion,

philosophy and theology, and using

Science: biology, experimental psychology, etc.

Simone de Beauvoir:

The Second Sex (1949)

Written by Angela Saini

Translated by Li Guanfeng

Cambridge University in late summer, with leaves beginning to turn yellow, must be as beautiful as it was when Darwin was a student in the early 19th century. In the quiet, towering northwest corner of the university library, traces of him remain. I sit at a leather-topped table in the manuscript room, holding three letters, their paper yellowed, their ink faded, their folds browned. Together, they tell a story about how women were viewed at the most critical moment in the history of modern science, when the foundations of biology were being sketched out.

The first letter was to Darwin, written in impeccable handwriting on a small piece of thick white paper. It was dated December 1881 and was from a woman named Caroline Kennard, who lived in Brookline, a wealthy town outside Boston, Massachusetts. She was committed to the advancement of women and had a prominent role in the local women's movement, at one point fighting to get the police department to hire female investigators. She was also interested in science. Kennard's letter made a simple request to Darwin. It was based on a shocking experience she had at a women's rally in Boston. Someone, Kennard wrote, had taken the position that women "were, are, and always will be inferior" and claimed that the position was "based on scientific principles." The authority that encouraged this outrageous statement was a book by Darwin himself.

When I received Kennard's letter, Darwin was only a few months away from his death. As early as 1859, he published his most important work, On the Origin of Species, and 12 years later, The Descent of Man. These two books revealed how we developed characteristics that made us better at surviving and reproducing, evolving from simpler life forms to the humans we are today. This was the cornerstone of Darwin's theory of evolution based on natural selection and sexual selection, which exploded like dynamite in Victorian society and changed people's views on the origins of mankind. His scientific legacy has left people with no doubt.

Kennard’s letter naturally assumes that a genius like Darwin could not possibly believe that women were inherently inferior to men. His work must have been misinterpreted. “Given the enormous influence of your opinion and authority, if you see a fallacy, you should correct it,” she pleaded.

The following month, Darwin wrote back from his home in Down, Kent: “You raise a very difficult question.” Darwin’s reply was so illegible that it was copied verbatim on a separate sheet of paper and preserved with the original in the Cambridge University archives. But the most offensive thing about the letter was not the handwriting but its content. If the polite Mrs. Kennard expected the great scientist to allay her doubts and deny that women were in fact inferior to men, she was likely to be disappointed. “Although I consider the moral qualities of women to be generally superior to those of men, they are not intellectually inferior to them,” Darwin wrote. “And, from the point of view of the law of inheritance (if I understand that law correctly), it would seem to me to create great difficulties if they were intellectually equal to men.”

The reply did not end there. Darwin added that if this biological inequality was to be overcome, women would have to support their families like men. But this was not a good idea, as it might harm the happiness of children and families. Darwin told Kennard that not only were women less intelligent than men, but they were better off not yearning for a life outside the home. This negated everything Kennard and the women's movement at the time were fighting for.

What Darwin said in his private letters was consistent with what he explicitly said in his books. In The Descent of Man, he argued that males deal with tremendous pressure to win mates, and so over thousands of years of evolution they have acquired advantages over females. For example, male peacocks have evolved bright, fancy feathers to attract plain-looking females. Similarly, male lions have evolved bright manes. His point was that, from an evolutionary perspective, females are fertile no matter how dull they look.

They can sit back and choose their mates, while males must do their best to impress them and compete with other males to win their favor. According to this logic, for humans, fierce competition for women means that men must become fighters and thinkers. Over thousands of years, this has honed their minds and refined their physical fitness. Women are indeed less evolved than men.

Darwin also explained in The Descent of Man that “the chief difference between the two sexes in mental ability is that the male excels the female in every occupation which requires deep thought, reasoning, the exercise of the imagination, or the mere exercise of the senses and hands.” To him, the evidence was everywhere. The top writers, artists, and scientists were almost all men. He saw this inequality as a reflection of biological fact, and so he concluded that “man eventually became superior to woman.”

Reading them now, these statements are startling. If women had somehow managed to develop the same extraordinary qualities as men, Darwin thought, it might be because they were pulling at the hems of men’s coats, since babies, in effect, inherit qualities from both parents in the womb. In the process, girls would accidentally acquire some of their father’s superior qualities, “fortunately indeed, the law of the equal transmission of qualities to both sexes prevails throughout the whole family of mammals, otherwise the male would probably be as superior to the female in mental endowment as the peacock is more gorgeous in plumage than the peahen.” Only a touch of biological luck, he suggested, had saved women from being even more inferior to men than they were. Trying to catch up with men was a losing gamble, as much a battle against nature as it was a losing battle.

To be fair, Darwin was a man of his time. His traditional views on the social status of women were reflected not only in his own scientific writings, but also in the views of many prominent biologists of the time. His ideas on evolution may have been revolutionary, but his attitudes towards women were stubbornly Victorian.

We can guess what Kennard was thinking from her long, fiery reply to Darwin's letter. Her second letter was far less elegant than the first. Women, she said, contributed as much to society as men, far more than just domestic work. After all, it was only in wealthy, middle-class circles that women were exempt from working. For many Victorian families, a woman's income was essential to making ends meet. The gap between men and women was not in how much work they did, but in what kind of work they were allowed to do. In the 19th century, most professions, including politics and higher education, were closed to women.

So when women did work, they were often confined to low-paid jobs such as housework, laundry, or work in textile mills and factories. “When the husband works a few hours a week and brings home only … a small income for his wife, who is the real breadwinner? They sacrifice themselves day and night, constantly, and carefully calculate and earn every penny for their loved ones,” Mrs. Kennard wrote.

At the end of the letter she wrote angrily: "Please allow women to have the same 'environment' with equal opportunities as men, and then make a fair judgment on whether they are inferior to men in intelligence." We have no way of knowing how Darwin would have responded to Kennard's reply, because no further correspondence between them can be found in the library archives.

But we know she was right, and that Darwin’s scientific ideas reflected the social beliefs of his time, which influenced people’s views on women’s abilities. Such ideas came from a long line of scientific thinking that dates back at least to the Enlightenment, when reason and rationalism spread across the European continent, changing people’s views on the human mind and body. “Science was embraced as the knower of nature,” Ronda Schiebinger explained to me. Women were portrayed as belonging to the home (the private sphere), while men were in the public sphere. The mother’s work of bearing children was to nurture new citizens.

In the mid-19th century when Darwin presented his work, the image of women as weaker and intellectually simpler was a common assumption. Wives were expected to be virtuous, passive, and submissive to their husbands. The English poet Conventry Patmore perfectly captured this idea in a popular poem of the time called "The Angel in the House": "Men must be pleased; and to please men / Is the joy of women." Many people at the time believed that women were not naturally suited to professional work, that they did not need to have a public life, and that they did not need to vote.

When these biases met evolutionary biology, they created a particularly toxic mix that would poison scientific research for decades. Prominent scientists made no secret of their view that women, like Darwin, were the inferior half of humanity.

Indeed, it is hard not to be shocked to read some of what leading Victorian thinkers said about women today. In 1887, the evolutionary biologist George Romanes (and friend of Darwin) published an article in Popular Science Monthly in which he pretentiously praised the “noble” and “lovely” qualities of women, including “beauty, propriety, gaiety, fidelity, and wit.” But like Darwin, he insisted that no matter how hard women tried, they could never reach the intellectual heights of men: “From the long-standing feeling of weakness and the dependence which follows, there arises in women a deep-seated desire to please the opposite sex, a desire which begins with the fear of slavery and culminates in the devotion of a wife.”

Meanwhile, in their 1889 bestseller The Evolution of Sex, Scottish biologist Patrick Geddes and naturalist John Arthur Thomson argued that women and men were as different from each other as the passive egg and the vigorous sperm. “The differences between the sexes may be exaggerated or reduced, but to abolish them, all the steps of evolution must be repeated on a completely new basis. What has been determined in the prehistoric protozoa cannot be undone by an Act of Parliament,” they said, clearly mocking the women’s fight for the right to vote. Geddes and Thomson’s 300-page treatise, filled with tables and line drawings of animals, outlined how they saw women as auxiliary to men (as the breadwinners’ wives) and never as equals.

Another example is Darwin’s cousin Francis Galton, who was dedicated to measuring the physiological differences between people. Among his many bizarre research projects was a so-called British “beauty map” produced in the late 19th century, which secretly observed women in different parts of the UK and ranked them from ugliest to most beautiful. Men like Galton, wielding their rulers and microscopes, reinforced sexism as something that could not be challenged. Through measurement and standardization, they gave what should have been seen as absurd projects a veneer of scientific respectability.

Taking on such a male scientific establishment was not easy. But for women like Kennard in the 19th century, there was no time to lose. They were fighting for their fundamental rights, as they were not even recognized as full citizens. It wasn’t until 1882 that married women in Britain were given the right to own and control their own property; and in 1887, only two-thirds of American states allowed married women to keep their earnings.

Kennard and others in the women’s movement realized that the argument about women’s inferiority could only be won on an intellectual basis. Women had to defend themselves with science, just as the male biologists who attacked them had done. The English writer Mary Wollstonecraft, who lived a century earlier, urged women to educate themselves… “The moral and intellectual progress of mankind must be constantly examined…until women are more reasonably educated,” she wrote in A Vindication of the Rights of Woman in 1792. The same view was shared by the prominent Victorian suffragists, who used the education they were allowed to receive to question what was written about women.

The emerging and controversial field of evolutionary biology became a clear target. Antoinette Brown Blackwell, believed to be the first woman ordained as a minister by a recognized Protestant denomination in the United States, accused Darwin of being negligent on issues of sex and gender. Meanwhile, American writer Charlotte Perkins Gilman (author of the feminist short story The Yellow Wallpaper) turned Darwinism on its head and proposed a reformation. Half of humanity, she argued, had relegated the other half to a lower stage of evolution. With equality, women would finally have the chance to prove themselves as good as men. Gilman was ahead of her time in many ways, such as opposing the rigid divisions between boys’ and girls’ toys, and foreseeing how the growing army of working women would change society in the future.

But there was a Victorian thinker who challenged Darwin’s authority in her own field, passionately and persuasively arguing in her book that women were no less scientific than men.

"There is no doubt in my mind that the history of life on Earth presents an unbreakable chain of evidence that confirms the importance of women."

Deviant ideas can emerge anywhere, even in the most conservative areas.

The town of Concord, Michigan, is such a place. With a population of just over 3,000, it is almost entirely white. The most famous attraction in the area is a well-preserved post-Civil War house with a gray clapboard roof. In 1894, shortly after the house was built, a local middle-aged female teacher expressed the most radical views of the time. Her name was Eliza Burt Gamble.

We don’t know much about Gamble’s personal life, except that she was a woman who had no choice but to be self-reliant. She lost her father at the age of two and her mother at the age of 16. With no one to rely on, she taught at the local school. Reports say she did well in school. Gamble also married and had three children, two of whom died before the end of the century. Gamble could have lived a conventional life like most middle-class women of the time, becoming the kind of demure, submissive housewife that Coventry admired. But she joined the growing suffrage movement and fought for equal rights for women, becoming one of the area’s most important activists. In 1876, she organized the first women’s suffrage convention in her home state of Michigan.

Gamble believed the cause was about more than just ensuring equality under the law. She acknowledged that one of the biggest sticking points in the fight for women's rights was that society had grown to believe that women were inherently inferior to men. But she was adamant that this idea was ridiculous, and starting in 1885, Gamble sought solid evidence for her beliefs. She spent a year researching the collections at the Library of Congress in the nation's capital, gathering evidence from various books. She was driven, she once wrote, "to see nothing but the thirst for information."

Despite Charles Darwin's denigration of women in his writings, the theory of evolution actually held great promise for the women's movement. It opened the door to a new evolutionary approach to understanding humanity. "Evolution was meant to be a way of modernizing," says Kimberly Hamlin, who charts women's responses to Darwin in her 2014 book From Eve to Evolution: Darwin, Science, and Women's Rights in Gilded Age America. Evolution offered an alternative narrative to religious stories that portrayed women as little more than a rib to men, challenging Christian models of female behavior and virtue. "Darwin created a space for women to say that the story in the Garden of Eden didn't happen... That was huge. It's hard to overstate how important Adam and Eve were in constraining and shaping human ideas about womanhood."

Though not a scientist himself, Gamble realized through Darwin’s work that the scientific method could also be deeply destructive. If humans, like all other life on Earth, were descended from lower creatures, it didn’t make sense for women to be confined to the home, or to be subservient to men. Because in other areas of the animal kingdom, the rules were clearly not that way. “It’s not natural for women to sit around and be completely dependent on men,” Hamlin told me. We can rewrite the story of women.

Despite the revolutionary potential of his ideas, Darwin himself never recognized women as intellectually equal to men. This was not only a great disappointment to Gamble, but also a source of great anger in her writings. Gamble believed that Darwin was correct in concluding that humans, like all other creatures on Earth, evolved, but he was clearly wrong about the role of women in human evolution.

Gamble expressed these critical views vehemently in his 1894 book, The Evolution of Woman: An Inquiry into the Dogma of Her Inferiority to Man (hereinafter referred to as The Evolution of Woman).

This book, a collection of history, statistics and science, is Gamble's tit-for-tat rebuttal to Darwin and other evolutionary biologists. She indignantly points out their inconsistencies and double standards. Male peacocks may have more gorgeous feathers, she says, but female peacocks must also hone their abilities in the process of choosing the best mate. Darwin conceded that gorillas were too big and too strong to evolve into more advanced social animals like humans, but he also used the fact that males are, on average, stronger than females to prove their superiority.

Gamble believes that Darwin also failed to notice that human qualities that are more commonly associated with women, such as cooperation, nurturing, protection, egalitarianism, and altruism, must have played a vital role in human progress. From an evolutionary perspective, it is narrow-minded and dangerous to infer their abilities based on the attitudes of society at the time towards women. Gamble believes that throughout human history, women have been systematically oppressed by men and patriarchal structures. Women are never born inferior, they seem inferior to men only because they have not been given the opportunity to develop their talents.

Gamble also points out that Darwin failed to consider that there were powerful women in some tribal societies, which may indicate that the current supremacy of men has not always been the case. She cites the ancient Hindu scripture Mahabharata as an example, saying that according to the scripture, women are independent and unfettered before marriage. So she can't help but wonder, if the "law of equal transmission" applies to men and women, then why can't men be dragged forward by the outstanding women in the community?

She argued: "If a man and a woman are put into competition, both of whom have perfect mental qualities, but one has more energy, more patience, and to a certain extent stronger physical advantages; while the other has better intuitive abilities, more acute and quick perception, and to a certain extent greater endurance... the competitive advantages of the latter are undoubtedly equal to those of the former."

Like other suffragists with a scientific bent, Gamble’s message caught on. The provocative implication was that women were being deprived of their right to life, that equality was in fact their birthright. In 1916, Gamble wrote in the preface to the revised edition of The Evolution of Woman: “There can be no doubt in my mind that the history of life on earth presents an irrefutable chain of evidence which establishes the importance of woman.”

But the support she received from her readers and other activists failed to win biologists over to her ideas. Her ideas were destined to never fully enter the scientific mainstream, and instead linger on the periphery. But Gamble never gave up. She continued to fight for women’s rights, writing articles for publications. Fortunately, Gamble lived long enough to see her work and the wider women’s movement gain real power. In 1893, New Zealand became the first self-governing country to grant women the right to vote. In Britain, the fight continued until 1918, although by then the franchise only applied to women over the age of 30. In 1920, exactly one month before Gamble’s death, the United States passed the Nineteenth Amendment to the Constitution, prohibiting the denial of the right to vote based on sex.

While the political battle was eventually won, the battle to change people's minds took longer. "While Gamble's ideas were celebrated in progressive magazines and her writing style was generally praised, the scientific community and the mainstream media were not impressed by her conclusions and her claim to be writing 'science,'" says Kimberly Hamlin. The Evolution of Women was widely discussed in newspapers and academic journals, but the book made little impact on science.

In 1915, a scathing review of Sex Antagonism, the latest book by the venerable British biologist Walter Heape, appeared in the American Journal of Sociology, pointing out that some scientists were clinging to their prejudices despite the changing social environment around them. “The publisher must have done it out of a sense of humor in putting this book in the ‘Science Series,’” wrote Albert Wolfe, a sociologist and liberal thinker at the University of Texas. Heape incorporated a vast body of knowledge about reproductive biology into his book and applied it half-heartedly to social issues, arguing that gender equality was impossible because men and women were designed for different social roles.

Many biologists at the time agreed with Ship's views, including John Arthur Thomson, co-author of The Evolution of Sex, who also gave a positive review of the book. However, Wolfe saw the danger of scientists overstepping their expertise. In his review, he ridiculed: "When a scientist, especially a biologist, who knows little about other fields outside his own specialty, dares to define what social and ethical relations should be based on the 'laws of nature' (which Mr. Ship claims to be the field he is most familiar with), he simply becomes a perfect example of psychopathology. He sees only disaster and pathology in the modern feminist movement."

Parts of science remain stubbornly inflexible and slow to progress. Evolutionary theory remains much the same as before, having learned few lessons from critics like Wolfe, Kennard, and Gamble. It is hard to imagine where science would have gone if society had not been so deeply sexist at the critical moment when Darwin was developing his theory. We can only imagine how differently society might have viewed women if Gamble had been taken a little more seriously. Historians today lament that her radical vision was a path not taken.

In the century since Gamble’s death, researchers have become increasingly obsessed with sex differences, with how to pick out, measure and categorize the differences between the sexes, reinforcing the dogma that men are somehow superior to women.

“…looking for gold in pregnant horse urine.”

It’s perhaps fitting that the next breakthrough in the science of sex differences may come from a castrated rooster.

In the 1920s, a series of new discoveries in Europe would change the way science understood the differences between men and women, just as Darwin and evolution had. These changes were foreshadowed in a strange experiment conducted by German medical professor Arnold Adolph Berthold in 1894. He had been studying castrated roosters, commonly known as capons. The removal of the testicles makes the meat of roosters more tender, making them a popular delicacy. In addition to the difference in meat quality, live capons also look different from ordinary roosters. They are more docile. In addition, the fleshy comb on the top of the capon's head is smaller than that of ordinary roosters, and the red wattle at the bottom of the chin is particularly droopy, which can be seen from the two.

For Berthold, the question is why?

He removed testicles from normal roosters and transplanted them into capons to see what would happen. He found that the capons began to look and sound remarkably like normal roosters again. The testicles survived and began to grow again. The results were astounding, but no one understood why at the time. What was in the testicles that helped the capons to seemingly turn back into normal roosters? Research into this question was slow to gain traction. In 1891, in another unusual experiment, a French university professor named Charles-Édouard Brown-Séquard finally began to get to the bottom of the mystery. He suspected that the testicles of male animals might contain some unknown substance that affected masculinity.

Then, in an attempt to prove his hypothesis the hard way, he repeatedly injected himself with a mixture of blood, semen, and juices from crushed guinea pig and dog testicles, which he claimed (though his findings have never been replicated) enhanced his physical strength, endurance, and mental clarity.

Brown-Séquard's discovery was reported with excitement in the British Medical Journal, which called his synthetic substance "the pentagram of rebirth." Other researchers later performed similar experiments using the female juices from the ovaries of guinea pigs and claimed to see the same feminizing effects. Over time, all the secret juices from male and female sex glands were understood to be a series of specific chemicals called "hormones."

We now know that the sex hormones found in the gonads are just a small fraction of the more than 50 hormones produced throughout the human body. We cannot live without these hormones. They act like lubricants for our body systems. Hormones are described as chemical messengers that carry messages throughout the body to ensure that the body functions normally, including development and maintaining a stable body temperature. From insulin to thyroid hormones, these hormones help the body regulate the function of various organs. Sex hormones control sexual development and reproduction. The two most important female hormones are estrogen and progesterone. Among other things, estrogen is one of the factors that cause breast development in women, and progesterone helps the female body prepare for pregnancy. Male hormones are called androgens, the most well-known of which is testosterone.

Even before a person is born, sex hormones play a crucial role in determining whether a person will look male or female. Interestingly, in the womb, all foetuses start out biologically female. "The default template for the foetus is female," says Richard Quinton, consultant endocrinologist at Newcastle upon Tyne Hospital. At around seven weeks after the egg is fertilized, testosterone produced by the testicles begins to transform the male foetus biologically into a boy. "Testosterone makes me look male on the outside," Quinton adds. At the same time, another hormone prevents the new male embryo from growing a uterus, fallopian tubes and other female organs. As we age, hormones come into play again during puberty and beyond.

It is no surprise, then, that the discovery of sex hormones became one of the milestones in understanding what it means to be a man or a woman.

According to the work of Nelly Oudshoorn, a social researcher now at the University of Twente in the Netherlands, hormone research sparked a wave of enthusiasm in the pharmaceutical industry in the 1920s. Suddenly, a scientific way of understanding masculinity and femininity emerged. With some effort, pharmaceutical companies believed they could isolate sex hormones and produce them industrially to make people more masculine or feminine.

Endocrinology, the new and controversial field of hormone research, is becoming big business. Scientists are desperately searching for the chemical that defines maleness or femaleness, harvesting tons of animal ovaries and testicles and collecting thousands of liters of horse urine. The head of the Dutch pharmaceutical company Organon describes the process of isolating hormones as "looking for gold in pregnant horse urine."

Almost a decade later, treatments based on sex hormones began to appear, promising seemingly limitless cures. In the archives of London’s Wellcome Library, a vast repository of historical medical texts, I found an advertising pamphlet from circa 1929 produced by the Middlesex Laboratory of Glandular Research in London. The ad proudly announced that the “flame of life” could finally be renewed, with “fresh glandular sex hormones extracted from healthy animals (e.g. bulls, rams, stallions) for male impotence, frigidity, and infertility.” Treatments containing estrogen claimed to have the same effect on women, promising to cure menopause, menstrual irregularities, and a variety of other symptoms.

Of course, hormone therapies didn’t live up to the hype, but they weren’t just a fad. Although the evidence was anecdotal, they did seem to work for certain symptoms. A 1930 article in the Lancet reported on a man who was treated with testosterone and found that his “muscles had grown stronger, and he felt more aggressive, coming close to getting into a physical altercation with a colleague.” Another man, 60, “could play 36 holes of golf in a day without feeling overly tired.” Testosterone came to be associated with traits considered masculine, such as aggression, physical strength, high intelligence, and virility.

Similar studies were conducted on women who took estrogen. In another article published in The Lancet in 1931, researcher Jane Katherine Seymour suggested that estrogen was associated with femininity and fertility. Under their influence, she added, women “tend to develop a more passive and emotional, and less rational, attitude toward life.”

In the early days of endocrinology, assumptions about what it meant to be masculine or feminine came from the Victorian era. With the discovery of hormones, scientists had a new way to explain stereotypes. For example, William Blair-Bell, a famous British gynecologist, was convinced that a woman’s psychology depended on “the state of her internal secretions” that kept her “within the normal range of behavior,” according to Anne Fausto-Sterling, a professor of biology and gender studies at Brown University in Rhode Island. The normal range of behavior, at the time, meant being a wife and a mother. If a woman crossed these social boundaries, scientists like him would say that something must be wrong with her hormone levels.

In other words, the researchers believed that sex hormones affected more than just reproductive behavior. They were what made men more masculine by the standards of the time, and women more feminine by those standards. Reasoning this way, scientists imagined that sex hormones were unique to each sex. Male hormones, called androgens, could only be produced by men; female hormones, called estrogen and progesterone, could only be produced by women. After all, if sex hormones were the key to masculinity and femininity, how could it be any other way?

In 1921, an intriguing experiment suggested that everything scientists had assumed about sex hormones might be wrong.

A gynecologist from Vienna revealed that treating female rabbits with extracts from animal testicles changed the size of their ovaries. Then, to the astonishment of scientists, they began to realize that both androgens in women and estrogens in men were high. In 1934, German gynecologist Bernhard Zondek reported that "it is contradictory to define a man by high androgen levels" while studying stallion urine. In fact, the horse's testicles were found to be one of the highest sources of estrogen to date.

Just when endocrinologists thought they had a handle on the effects of sex hormones, the discovery threw everything into disarray and raised a fascinating dilemma: If estrogen and testosterone determine female and male characteristics, why are both men and women born with both hormones? And what does it mean to be born male or female?

For a while, some scientists believed that estrogen might appear in men because they ate things that contained estrogen. This bizarre "food hypothesis" was eventually abandoned because people gradually realized that male and female gonads can actually produce both sex hormones on their own. Others believed that the only effect of estrogen on men was to deprive them of their masculinity, making them more feminine, and even potentially leading to homosexuality.

It took scientists some time to accept that these hormones were working in concert in both sexes. Nellie Oldsom describes how important this shift was to the way science understood gender. It was as if a spectrum had suddenly opened up, where men could be more feminine and women could be more masculine, rather than one against the other. Herbert Evans of the Institute for Experimental Biology at the University of California, Berkeley, described this period as “an age of confusion,” and at the end of it, in 1939, he wrote that “it seems that masculinity or femininity cannot be regarded as meaning the presence of one hormone or the absence of another… Although we have learned something about it, it is still not entirely clear what the difference is.”

The impact of this change in thinking was striking. The very concept of what it meant to be a woman or a man was already controversial. Researchers in other fields had begun to explore the boundaries of sexual and gender identity. Around the same time, American cultural anthropologist Margaret Mead began writing about masculine and feminine personality traits, and how culture, rather than biology, might influence the traits that each person possessed. “Samoan boys are never under undue pressure to display masculine traits, and the ambitious, managerial girl has many outlets in the busy, orderly life of the women’s community,” she wrote in 1949 while studying the Samoan tribe. She also noted that the Mundugumor culture of Papua New Guinea also produced more stereotypically masculine women.

Today, while not everyone agrees with Mead’s observations, her ideas do foreshadow a change in society that is being driven in part by science. The Victorian orthodoxy that Darwin embraced has radically changed. Gender is no longer neatly defined. There is overlap. Female and male, femininity and masculinity are shifting into dynamic descriptions that may be shaped as much by nurture as by nature.

This revolution in scientific concepts about what it means to be a woman came just in time for the 1960s and 1970s, the second wave of feminism that had won women the vote decades earlier. Women biologists, anthropologists, and psychologists were entering universities and graduating in increasing numbers. They were becoming researchers and professors, helping to usher in another era for women’s studies. New ideas challenged long-standing narratives.

A new generation of scientists is following in the footsteps of their predecessors, a path pioneered by Darwin-challenging feminist pioneer Gamble in the last century.

The time has come to today.

Stereotypes about sex hormones persist. But these old ideas are constantly challenged by new evidence. According to research by Richard Quinton, common assumptions about testosterone have been proven to be completely wrong. He says women with slightly above-average testosterone levels "don't actually feel or look any less feminine".

In 2008, John Coates, a former Wall Street trader and neuroscientist at Cambridge University who specializes in risk taking and stress biology, decided to see how true the old saying that stock market trading floors are testosterone-filled reservoirs of macho energy was. He took saliva samples from traders and found that when their testosterone levels were above average, their returns were also above average. In 2015, another study by a large team of researchers from the UK, US and Spain showed that testosterone didn’t make traders more aggressive, it just made them slightly more optimistic. And that might make them take more risks when predicting future changes in stock prices.

Similarly, Richard Quinton claims that, despite the stereotype that testosterone makes people violent, he has not seen a link between testosterone and aggression in his own patients. “I don’t know where that comes from,” he told me. “Is it an urban legend?”

People are beginning to understand a little better the balance between nature and nurture. At least in academic circles, gender and sex are seen as two different concepts. Sex is what science distinguishes for most people. It is defined by a set of genes and hormones, as well as more specific physical features, including a person's genitals and gonads (although a small number of people are biologically intersex). Gender, meanwhile, is a social identity that is influenced not only by biology but also by external factors such as family upbringing, culture and stereotypes. Gender is defined by the outside world's representation of what it means to be male or female, which makes it potentially mutable.

Many people's biological sex and social gender are different. But we're still in the early stages of this research. The biggest questions remain unanswered. Do the effects of sex hormone balance extend beyond our sex organs, into our minds and behaviors, causing clear differences between men and women? What does this tell us about how we evolved? Is the traditional stereotype of breadwinner fathers and stay-at-home mothers really part of our biology, as Darwin imagined, or a complex social structure unique to humans? The study of sex differences is both influential and controversial. Just as 20th-century research on hormones challenged popular ideas about masculinity and femininity, science is now forcing us to question every aspect of ourselves.

When the facts emerge, they matter. In a world where so many women still suffer from sexism, inequality, and violence, facts can change the way we see each other. With good research and solid data (and clear facts), the strong can become weaker, and the weak can become stronger.

About the Author

Angela Saini, a master of engineering from Oxford University, a researcher at MIT, a British science journalist and program host, has published: "Geek Empire: How a Weird Nation in a Laboratory Shakes the World". She also contributes to major publications such as "Science", "Wired", "The Guardian", and "New Scientist". She is also a program host for BBC Radio. She has won awards from the British Association of Science Writers and the American Association for the Advancement of Science, and was named European Science Journalist of the Year.

This article is reproduced with permission from "Inferior: What Science Did Wrong to Women" (Chongqing University Press), and the title is added by the editor.

Special Tips

1. Go to the "Featured Column" at the bottom of the menu of the "Fanpu" WeChat public account to read a series of popular science articles on different topics.

2. Fanpu provides a function to search articles by month. Follow the official account and reply with the four-digit year + month, such as "1903", to get the article index for March 2019, and so on.

Copyright statement: Personal forwarding is welcome. Any form of media or organization is not allowed to reprint or excerpt without authorization. For reprint authorization, please contact the backstage of the "Fanpu" WeChat public account.