Men who have been thought of as philosophers and scientists have generated and perpetuated the myth that men and women are essentially different. Supposedly, men understand how to build and work with systems, while women are better empathizers. Many believe that males and females can be easily differentiated based on their intelligence, aggressiveness, mechanical skills, spatial visualization, empathy, agreeableness, communication skills and other characteristics1,2. Supposedly, the differences between a man and a woman’s brain are due to differences in their genes, which code for specific hormones that “hardwire” the brain to be either male or female3. This is based on reductionist thinking and sexism. However, it is important to recognize the important differences that do exist between men’s and women’s health. So, the aim of this article is to dispel the myths that our brains are hardwired at birth to display many male or female characteristics, while describing genuine differences between the sexes in their health and healthcare needs.

Systems Thinking

In contrast to reductionist thinking, modern biology and medicine use systems thinking to recognize that our genes are not a blueprint and we are not machines that can be hardwired4. We are dynamic, living systems that undergo continuous change – especially in our brains4. The genes and proteins that they encode are subject to epigenetic changes caused by our lifestyle and environment. This includes the socialization and conditioning that most of us receive throughout our lives. That is, sex is a term that refers to the hormonal and genetic components of sex (like a Y chromosome). On the other hand, gender is a social construct that creates “expectations concerning the roles, identities, and behaviors associated with being either female or male” 5. “Both sex and gender can affect brain and behavior, either independently or in interaction” 5. The belief that hardwired differences in male and female brains exist has caused extensive damage2. The self-fulfilling prophecy of differences helps drive prejudicial attitudes and differences in how boys and girls are taught from the earliest ages. There are few, if any limits to mental ability that are imposed by biology or genetics. Instead, there are “restrictions imposed by society”2.

Myths and responsibilities

It’s important to expose dangerous myths, while understanding that girls and women can do anything that boys and men can do. We must realize this. The health of the planet and human civilization depend on it. The same misogynistic attitude that treats women as commodities to be used and discarded treats the environment the same way. As described in Trends in Cognitive Sciences by Rebecca Jordan-Young, Anelis Kaiser, Cordelia Fine and Gina Rippon, scientists who are studying sex differences have an important responsibility6. They must realize “how social assumptions influence their research and, indeed, public understanding of it” 6. They must “recognize that there are important and exciting opportunities to change these social assumptions through rigorous, reflective scientific inquiry and debate” 6. One assumption that should be challenged is that one’s intelligence and behavior are static or hardwired by the genes we inherit from our parents. We should also challenge the terrible way results are often portrayed - for example: “New study finds that men are systematic and women are empathetic” or “Men Are from Mars and Women Are from Venus”. If all men are from Mars (the ancient Roman god of war), while all women are from Venus (the goddess of love), what planets were Dr. Martin Luther King and Mahatma Gandhi from?

Often, myths are perpetuated by people who oversimplify the results of studies. When scientists or psychologists report finding a statistically significant difference between men and women, this is often reported as meaning that all men and women display the difference2. This is not true even when comparing obvious differences. Just because the average height of women is less than that of men, there is considerable overlap. You can’t tell if someone is a man or a woman simply based on their height2. Neither can you tell if a tall person is a man or a woman simply because he or she is tall. So, the statement, “Men are taller than women” is false.

Similarly, statements like “men are more analytical than women” imply that all men are more analytical than all women. This is unfair. To illustrate this point, how would men feel if they read this headline: “Men are murderous and evil while women are healers who do good things” because “a recent study” found that men start wars, own slaves, commit genocide, and perpetrate about 96% of all homicides worldwide7? Of course that is unfair. The vast majority of men do not own slaves, start wars, commit genocide, rape or murder. Even though some men do these things, they were not hardwired or destined to do so from birth. Still, there is a popular belief among many men that males and females have fundamental or ‘essential’ qualities that make them what they are. It argues that women and men are distinctly, immutably and naturally different. “Essentialist thinking involves beliefs that that one group is natural, immutable, discrete, informative, historically and cross-culturally invariant and grounded in deep-seated, biological factors” 8. In general, essentialist thinking serves to justify social inequalities, slavery and even genocide8.


Even if a study were to find statistically significant differences between the average characteristics of men and women, it does NOT mean that all men and women have these differences2,9. There can be as much as 90% overlap between the two groups (male and female). Moreover, identifying statistically significant differences says nothing about cause and effect. Finding a link between two things (like intelligence and gender) does NOT mean that one thing causes the other. That is, linkage does not imply causation. The gendered society that treats boys and girls differently often causes them to develop different mental abilities. The different abilities usually are not caused by being born male or female. They are caused by the teachings and expectations of a gendered society. Through such biased gender training, the average characteristics of brains can change. They were not hardwired with such differences2.

When a study finds a statistically significant difference between two groups, it says nothing about whether the difference has any meaning or can predict anything2. The ability to predict depends on the effect size, or amount of overlap. Many studies on male and female brains had an effect size of only about 0.2. There was so much overlap between males and females that it was impossible to distinguish between members of each group or predict what any member of each group can or can not do. Even when the effect size is much larger (2.0), as in the differences in height of men and women, you can’t make accurate predictions2. Unfortunately, many of the widely cited reports on sex differences in mental abilities either did not report the effect size or that they had low effect sizes. So, it would be wrong to say that men and women have different mental abilities based on such studies2.

Our brains and abilities change throughout life

Our brains and abilities change throughout life, through training, education and experience. Even though many boys and young men may be better at math than many girls and women or have better mechanical or spatial skills, this often changes as we age. For example, most of the women with whom I play cards are over 80 years old. They have infinitely better mathematical and mechanical skills than the men to whom they were married – because they are widows. Some were even married to physicians who died of lung cancer from smoking. Fortunately, it was considered unladylike to smoke. So, who was smarter – the physician with all his knowledge or his wife, who never smoked? When they were younger, the physician had the higher IQ and was considered to be more intelligent. He probably didn’t feel very smart or wise when he was diagnosed with lung cancer.

There is a difference between knowing many facts (knowledge) and making proper or wise decisions (wisdom) 10. Wisdom is more than knowledge. It needs humility, as well as recognizing that uncertainty and change are inevitable. Wise thinking varies from one situation to another. Experiential, situational and cultural factors are very powerful in shaping and evaluating what is wise thinking. The situational context is embedded in experiential context. Both are embedded in sociocultural context. For example, there are fundamental differences in the concept of self in the West, compared to China, South Korea and Japan10. Even though wisdom may be defined differently in various cultures, most (if not all) cultures consider wisdom to be more important than knowledge or even intelligence. Still, these can and do change throughout life.

The importance of our diet and second brain

It's also important to realize that one’s overall health will also affect one’s intelligence and behavior. If a person has cancer, irritable bowel syndrome or other serious diseases, it can be hard to stay unemotional and analytical (like a man should?). We are not hardwired and fated to suffer from diseases that are caused by poor diet, a sedentary lifestyle or environmental pollutants. Such factors can lead to an unhealthy imbalance (dysbiosis) in the bacteria and nerves that are in our gut, or enteric nervous system (ENS) 11. Eating fresh fruits and vegetables, as well as whole grains provides dietary fiber that leads to a healthy gut microbiome12. By making intelligent choices in our diet and lifestyle, we can help form a healthy ENS. This, in turn, can keep us healthy and happy, leading to emotional stability and improved intelligence. So, the ENS can be thought of as our second brain and internal oncologist12. It helps us make good decisions (both consciously and unconsciously) and helps prevent cancer. In addition, environmental factors, training, education and peer pressure can affect our intelligence and behavior. The brains in our skull and our ENS are quite flexible (have plasticity). Both brains change constantly and subsequently change us throughout life. They are not hardwired.

A gendered society can produce a gendered brain

Still, scientists report finding differences in the average brain structure or behavior of men and women. Remember, cause and effect can be difficult to distinguish. Even when significant differences are found in the average brain structure or behavior of men and women, this says nothing about the cause. That is, after decades of social conditioning our brains can be expected to be affected. The differences in the average brain structure or behavior of men and women are more likely to be due to epigenetic changes and changes in brain connectivity caused by social conditioning than by the genes that they inherited from their parents. Sometimes, the differences are partly explained by different life experiences. The incidence of Alzheimer’s Disease (AD) is higher in women than in men – partly because women tend to outlive men and age is a strong risk factor for AD. Also, it has been my experience that no baby is born more aggressive than another baby or with any better mechanical skills. Aggressiveness depends on the situation. Even though boys and men are encouraged by society to be aggressive, nothing can match the aggressiveness of a mother who is defending her children! In addition, throughout the first 40 years of my life, I had low self-esteem because I had miserable mechanical and spatial visual skills. I never met a girl or woman who had worse spatial skills than me. I could not visualize the three-dimensional shape of an object after seeing two-dimensional views of the top, side and bottom of the object (spatial visual skills). When I was 40, I began making plastic models of proteins and DNA based on the structures that were freely available on the Protein Data Bank13. When I looked at the two-dimensional images that were on the Data Bank and compared them to the three-dimensional models, I improved my spatial visual skills.

Flawed studies

In addition, many of the studies that reported seeing differences in the structures of men’s and women’s brains were fundamentally flawed2. They used functional magnetic resonance imaging (fMRI) to look at the brains. Even though MRI is very useful in identifying brain tumors, it can be misinterpreted when looking at brains while people are doing a specific task or function. Unfortunately, fMRI is often reported as being able to measure brain activity. It actually measures changes in blood flow. It does not measure the passage of nerve impulses that occur within milliseconds when we are doing a specific task. The changes in blood flow occur much slower – on a scale of several seconds. Even more unfortunately, fMRI can produce colorful, seductive images that do not show real time brain activity – even though they are interpreted as doing so. This has been described accurately as ‘neurotrash’. These misleading images have been used by the popular press and authors of self-help books to try to sell the nonsense that men’s and women’s brains are essentially different. These pictures have helped make such nonsense seem scientific and true2.

Actually, the differences in blood flow that fMRI shows are quite small2. The operator of the fMRI machine can set the threshold so that it will make the computer display colorful differences. If the threshold is set too high, real differences will not appear. If the threshold is too low, differences can appear that are obviously false2. This was shown in a study by Craig Bennett and colleagues at Dartmouth University2,16. They wanted to use fMRI to look for brain activity in an emotion recognition study. They wanted to have a negative control – a subject that would never be able to recognize the differences between happy or sad faces. They chose a dead salmon. They set the contrast on their fMRI at levels high enough to show emotional activity when it actually occurred in humans. To show the limits of the method, they also showed what happened when the thresholds were set too low. They were able to produce colorful pictures that seemed to find an area of the brain that was more highly activated when the dead salmon was shown happy or sad faces than when the salmon was ‘at rest’2,16.

Real differences

Still, there are sex differences in health. Women tend to live longer than men15. Women are also less susceptible to oxidative damage and liver disease, as well as age-dependent diseases and chemical-induced toxicity16. The prevalence, average age of onset and symptoms of many neuropsychiatric conditions are different between men and women. On average, men have larger brain volumes. There are differences in the average volume and tissue density in the amygdala, hippocampus and insula. These areas of the brain are thought to be important in sex-biased neurological conditions. Male-biased psychiatric conditions include autism, attention deficit/hyperactivity disorder (ADHD), conduct disorder, specific language impairment, Tourette syndrome and dyslexia. Female-biased psychiatric conditions include depression anxiety disorder and anorexia nervosa15. So, it’s important to realize that there are differences in women’s and men’s health when developing precise medications for each group17.

For example, the Women’s Health Initiative (WHI) conducted three clinical trials and an observational study to help prevent heart disease, breast and colorectal cancer, and osteoporosis in postmenopausal women18. The WHI is currently conducting ancillary studies to examine the health benefits of a physical activity program in older women, the use of wearable devices to measure the effect of physical activity on cardiovascular health in older women and whether sleep-disordered breathing and the resulting low levels of oxygen in the blood are associated with an increased risk of cardiovascular events18. There is also a Women’s Brain Health Initiative19. As stated on their website, “It was frightening to learn that women suffer from depression, stroke and dementia twice as much as men and an astounding 70% of new Alzheimer’s patients will be women. Yet research still focuses on men. We want to correct this research bias” 19. There have also been medical biases against women18. For example, women have been excluded from many clinical trials in the past. Also, verbal memory tests used to detect the early stages of Alzheimer’s disease (AD) tend to produce false negatives in women because they tend to perform better than men. Since this difference is not taken into account, AD is often detected later in women. This can prevent earlier treatment18.

Things that are being done

Gender equality is a fundamental human right. It is an essential part of the UN’s Sustainable Development Goal 5 and is necessary for the well-being of everybody20. The Bill & Melinda Gates Foundation is making a huge contribution. They are “dedicated to the principal that everyone should have the opportunity to lead a healthy and productive life”21. They co-funded the work that led to a special Series in the prestigious British medical journal, The Lancet. It discussed gender equality, norms and health. We must meet national and international goals for universal healthcare and access to contraceptives. We must fund initiatives like Gavi, the Vaccine Alliance, as well as the Global Fund to Fight AIDS, Tuberculosis and Malaria23. This special Series focused on gender norms, their measurement and how they contribute to health outcomes22. Gender inequalities emerge from systemic inequalities in power that reinforce disadvantage and discrimination of girls and women23.

Sexism and patriarchy work with racism, classism and homophobia to cause poor health24. The things that are considered to be masculine or feminine reflect a hierarchy in which masculine is superior to feminine. Biology, social power and social experience work with a gendered system to create inequalities in healthcare. This system teaches adolescent boys that they should be tough and exhibit sexual prowess, while girls are held responsible for attracting the attention of men. Female physical beauty is defined almost arbitrarily, but becomes very important in a patriarchal society. Many women use toxic cosmetics. The need to appear thin has driven the sexist marketing of weight loss supplements and so-called superfoods. In some countries, breast implants are popular, even though they can lead to chronic back pain as a woman ages or has children. In some societies, many girls’ opportunities are restricted when they reach puberty, while boys’ opportunities and freedoms expand, as long as they belong to the right socioeconomic or ‘racial’ class. Research is showing that the question is not whether genes or environment affect health (nature vs nurture). Instead, researchers are learning how genetics interacts with the environment to shape personalities, intelligence and overall health. Chronic stress, especially in childhood, often leads to a higher risk of cardiovascular diseases, autoimmune disorders, post-traumatic stress disorders, depression and premature mortality. Individual stressors such as trauma can cause epigenetic changes. Stressors that affect an entire group (poverty, racism) can cause these changes too. Fortunately, there is a growing movement of men who support gender equality. This has led to the realization that gender inequality and paternalistic attitudes hurt boys and men, too24. There will be no truly free men until all women are free and have equal opportunities.

Efforts to involve men in the struggle for gender equality must lead them to real personal and social change25. Men who conform more to masculine standards (be tough, stoic, dominant, daring and in control) are more likely to assault and rape women, consider suicide, take risks with sexual partners and when driving, avoid seeking help and refrain from active fathering. Through love, education and a bit of personal effort, such men can change – they are not hardwired that way.


Our brains are not hardwired at birth to display male or female characteristics. Through a mixture of genetics, epigenetics, environment, training and motivation, we develop complex personalities. Despite the attempts of a gendered society to label us, most of us have some characteristics that are labeled masculine, mixed with others labeled as feminine. We should all have equal opportunities to lead full, rich lives.

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