I’m very late to the game on having a take on this Google manifesto guy, but apparently, as much as I thought he would disappear into the ether, he has become a darling of the conservative news circuit. Much has been made about the points Damore makes, particularly the statements regarding biological differences between men and women.

Yonathan Zunger, a former Google employee, provided a great counterpoint to what James Damore thinks the skills of an engineer should be. But, as I’m not a Google engineer (much to my family’s disappointment), I can’t speak to what skills are necessary to succeed there.

I’d like to discuss the biology behind the arguments Damore, before going into the statistics of the science he discusses, and confirming the general belief that he’s wrong and ignorant.

Damore makes several biological arguments for why women are unable to succeed and progress through the ladders of the company, rather than systemic sexism or socialized gender norms. The arguments he reports to support differences between men and women on a biological level include:

  • They’re universal across human cultures
  • They often have clear biological causes and links to prenatal testosterone
  • Biological males that were castrated at birth and raised as females often still identify and act like males
  • The underlying traits are highly heritable
  • They’re exactly what we would predict from an evolutionary psychology perspective

A lot of these arguments are bizarre and not grounded in anything I’ve ever heard of, but let’s break down Damore’s points about why men and women are different, from a biological context, and show why each of them are wrong.

They’re universal across human cultures

If gender roles that we find in Western culture are universal across human cultures, then there is in fact a biological root for gender disparity, rather than a socialized source. However, a simple Google would have shown Damore that our socialized norms are not universal, and indeed the experience of women and men around the world is fairly heterogenous. For example, the Khasi women of Meghalaya in India control society, men take their mother’s name, and feminine gender is applied to anything useful in their language (tree is masculine, but wood is feminine), and most men fall victim to alcohol/substance abuse because they don’t feel part of the society.  Mosuo women handle all business decisions, Minangkabau marriage is considered a financial “exchange of men”. There are also plenty of examples of third genders, or variations in traditional male/female Western gender roles in other cultures. Hijra in India, berdache in North America, the fa’afafine in the Pacific, and the kathoey in Thailand. There are plenty of examples to refute the idea that male/female gender roles are universal – I’m only listing the top 3 that came from the simplest of Google searches.

They often have clear biological causes and links to prenatal testosterone

This example is bizarre, because Damore is taking established science and using it to support his bizarre theory. The importance of prenatal testosterone was shown previously in a famous study where male monkeys were shown to have a preference for trucks while female monkeys prefer dolls. The study showed that prenatal testosterone predicted preference for male toys, and that this was evolutionarily conserved (as similar behavior was seen in monkeys).

However, while the research around toy preference and prenatal testosterone is fairly well supported, it remains unclear what impact prenatal testosterone has on gender identity or sexual preference. For example, females exposed to elevated prenatal testosterone will also prefer to play with trucks and weapons, and males that cannot respond to prenatal testosterone will prefer female-typical toys. So, just because you like playing with toys not typical of your gender, that does not mean that you will not be the gender/sex of your birth.

So, even though most men are exposed to prenatal testosterone, that does not mean that women are not exposed to prenatal testosterone (or that some men won’t be exposed to testosterone). While it is true that there are biological underpinnings to gender behavior, AGAIN, this is not universal.

Biological males that were castrated at birth and raised as females often still identify and act like males

WTF? No idea where he’s coming up with this. To my knowledge, the most common reasons for castration of males is with sex offenders, religious sects, court servants, and as a treatment for prostate cancer. Regardless, the common medical consequences of castration include reduction of sex drive, loss of muscle mass, memory, body hair, hot flashes like those that women at menopause, osteoporosis, shrinking of the penis, and almost complete loss of erectile function. I’d imagine that these physiological changes would severely hamper the ability of biological males to “act like males”, as Damore would view “maleness” anyway.

If Damore is referring specifically to one horrifically unethical instance that this happened, a psychologist who took a biological male child who had a botched circumcision and castrated him and forced his parents to raise him as a girl with the name “Brenda”. At age 9, he was convinced that this experiment was a complete success, because “Her behaviour is so normally that of an active little girl, and so clearly different by contrast from the boyish ways of her twin brother”. When the child reached puberty, he became suicidal and his parents finally told him that he was born a boy. He changed his name to “David” weeks later, and continued to be depressed and eventually killed himself. So, long story short, I’m not sure that this is a text book example of gender identity being rooted in biology. [As a note, I kept the pronouns for “David” male since he was born biologically male, and outside of this experiment forcing him to be female, he preferred a male identity. I kept the female pronoun since that’s what the psychologist, Dr. Money (seriously), used when describing him.]

The underlying traits are highly heritable

Again, not sure what traits Damore is referring to, but the previous points reflect the significant influence of hormones such as testosterone and estradiol on development of males and females, respectively. Biologically, sex is determined by inheritance of an X or Y chromosome. Obviously, there are associated sex-linked traits with inheritance of the sex-specific chromosome, but considering that at least 5% of all pregnancies have a sex chromosome disorder, this limits the possibility that sex-traits being purely heritable.

The issue of heritability gets even muddier as behaviors are some combination of environmental, genetic, and epigenetic factors. So, it is unclear A) which behaviors are products purely of genetic/epigenetic (heritable) factors, and B) what traits are 100% heritable (vs a response to environment).

They’re exactly what we would predict from an evolutionary psychology perspective

Damore makes probably the greatest leap here – that evolutionary psychology is genuine science, rather than hand-wavey pseudoscience. Most people have a very limited understanding of evolutionary science, which is why many fall into the traps of evolutionary psychology. Briefly, the idea behind evolutionary psychology is that human psychological behavior is driven by natural selection. Therefore, women are nurturing beings because they raise children while men are aggressive and violent because they are competing for women and to kill animals for food. The most nurturing women and the most aggressive high status men are going to have the most surviving offspring, and therefore will win out over other men/women pairs. Sounds very simple and easy to comprehend within traditional gender roles.

THAT BEING SAID, we assume traits like nurturing, empathy, aggressiveness, strength are 100% heritable (which as I mentioned earlier may not be true). A truly nurturing and empathetic female could get killed before she can have offspring, and a truly violent/aggressive male could get killed by an animal or get sick and die before he has offspring. Therefore, this “evolutionary psychology” notion overlooks the vast history of selective pressures driving human behaviors over time. Perhaps it was better evolutionarily to be a male coward and hide away while the other aggro males killed each other? Or it was better to be less nurturing so as to not get diseases from your children that would kill you?

Even if natural selection was uniform throughout human evolution, that does not mean that the traits we currently ascribe to men or women have been selected for. Exaptation, the coopting of traits not for their original purposes, may serve as a counterargument to the traditional explanations of gender roles. For example, the adaptive development of feathers may have originally served as selective features for birds to attract mates, but they also allowed birds to fly. A sexual feature was coopted to become a physiological feature. Comparably, it is believed that neurons in your brain involved in movement (mirror neurons), may also have been coopted for human empathy. So, behaviors we observe may not be due to natural selection FOR those behaviors, but are a product of natural selection producing these behaviors.

Adding to the complexity of variation in selection over time is the idea that not all genes are beneficial to human selection. Around 45% of our DNA is composed of retrotransposons and endogenous retroviruses (collectively called “retroelements). Compared to only 2% that encodes heritable information (genes), you can see that the vast majority of our DNA are retroelements. These are segments of DNA that spontaneously copy and paste themselves into other parts of your DNA. So, our DNA is replicating and changing itself, doing whatever it wants, independently of how it may affect us physiologically. Retroelements in mice are responsible for driving androgen (testosterone) expression, and our understanding of retroelement function in humans is still in the early stages.

If this [brief] discussion of evolution seems confusing and convoluted, I believe that underscores the point that evolutionary psychology is a vast oversimplification of the complex and varied processes involved in natural selection, and that the behaviors we observe in current humans have almost as much of a chance of being attributed to selection as they do to random chance.

Randomness and statistics

Hopefully by this point it’s clear that most of the biological arguments that Damore makes come from a VERY limited understanding of biology. One of the most egregious extrapolations of Damore’s arguments is that female brains are fundamentally different from male brains. Again, a simple Google would confirm that there are no differences between male and female brains.

Most interestingly, a study in 2015 examined 1500 brains and found no difference between male and female brains, stating “human brains do not belong to one of two distinct categories.”

However, there have been a few studies that suggest there are differences between male and female brains. These reports have been lapped up by popular media saying “men are good at directions, and women are more compassionate“, without a very important caveat. Differences found between male and female brain are significant, but what does that mean?

When you look at the studies on male vs female brains (particularly the one looking at men being good at directions and the one looking at male vs female brain size), you’ll notice that the results are significant, but this is comparing the “average” male vs the “average” female. If you look at these studies, you’ll see that the standard deviations, that is how far individuals in a population deviate from average, overlap. So, around 60-90% of male brains overlap with 60-90% of female brains. Further underscoring the point that there are no differences (really) between male and female brains.

Lastly, Republican brains have a diminished anterior cingulate cortex, the part of the brain involved in problem solving, which makes them less effective problem solvers (and probably worse engineers). So, there’s that.


  • There are no biological justifications to explain why women are not able to succeed in various professions. There are plenty of social justifications (sexism being the biggest).
  • F*** this dude.