For the better part of my life I have been hearing from my parents, their friends, my teachers and everyone
else in sight that this is for boys and that is for girls. I always heard how this toy or this piece of clothing or
this behavior or this way of doing things is appropriate for boys but not for girls or the other way around.
Growing up I never understood that. I have been on a quest since my teenage years to figure out what
everyone else seems to agree upon. I have been on a quest to find a “man’s nature vs. a woman’s nature”.

I am happy to report 20 years into this quest that such a thing does not seem to exist. I am happy to report
that it all seems to fit under human nature and not gender nature. Of course I have come across all the
pseudo-science trying to prove that men have a larger brain than women and that men are tougher than
women. There is a whole line of fake evidence trying to prove that a male brain is more developed
somehow that a female brain. In reality, there is no such thing. Brain size in males and females is almost
identical if you factor in the proportions to body size. On average men have a larger body than women and
consequently a proportionately larger brain size. Pound for pound of body weight, men and women have
identically sized brains.

There are countless studies showing striking differences between females and males of some species.
However, there are also countless studies showing almost identical features between females and males of
some other species. There are species with striking differences between male and female form and
behavior. There also as many species where the differences between male and female shape and behavior
as so minute that a discerning eye may not be able to make the difference. There are also species where
“assigned gender roles” are the reverse of what humans think them to be. The notion that the reproductive
role determines one’s life path and behavior is a notion introduced by insensitive men who find it very
convenient to subjugate women to their advantage. No further elaboration required.

There are also species where striking physical differences exist between females and males in a majority but
not in all members of the species. The human species seems to be such a species. Everyone can tell that
Arnold Schwarzenegger is a hyper-muscular male and that Maria Shriver is (or used to be) a hyper-
estrogenized female. On the other hand, one might have a more difficult time telling the gender of Liza
Minnelli from her ex-husband’s David Gest. In the latter case, the physical gender differences are sort of
blurred. All the mentioned examples represent normal human beings. They are just different versions of
normal. We can see that physical differences between the genders can be more or less striking within the
same species. In a sizable minority of human beings, apparent gender differences are minimal to non-
existent and hopefully one day everyone will see that multiple forms of normal from all parts of the
spectrum can simultaneously and peacefully co-exist. It is worth mentioning that many sensitive people
(females and males) fall into this minority of humans with less striking physical differences among the

Ever since the glaciers retreated and the last ice age ended some 15,000 years ago and we are in an age of
insensitive men writing history of men for the generations of insensitive men to follow. In the last 150 years
when modern science started creeping in, men have been trying to prove that women are behaviorally
inferior somehow. Where better to look than the brain. I am happy to report that so far no evidence has
been found despite the serious efforts. Every section of the human brain has been compared across genders
over and over to exhaustion. Besides sections specialized in reproductive functions and reproductive
behaviors, no meaningful differences have been found between genders.

It may be worth mentioning that one scientist found that men can distinguish noise from coherent language
more efficiently using the right ear than the left ear. On the other hand, women have the same
discrimination capacity between noise and language equally in both ears. No real difference was found
regarding the objective ability to perform the function in question. However, you see this non-existent
difference carried over in the mainstream arena as an incentive to look for more differences. They did find
that the right brain develops earlier in boy fetuses than in girl fetuses. It seems that the right brain is more
developed in boys while in girls both sides of the brain are more or less equally developed. However, there
appears to be no behavioral significance to this finding.

Another scientist found that women have more developed language centers than men. Surprise! Women are
encouraged since childhood to express themselves in words. They are taught these skills and that leads to
extensive development of the language and speech centers in the brain. When a little boy tries to express
how he feels he is discouraged in many ways since he looks undesirable to the parents due to their social
conditioning. It is very important to distinguish innate differences a person is born with from learned
differences induced by preferential upbringing.

Aside from the complementary procreative differences all attempts at proving the presence of gender-based
differences in the brain are futile. In fact documented differences are mostly the result of upbringing and
societal influence. Boys do not excel in sports due to some gender difference. Boys excel in sports because
they are trained and encouraged and rewarded in order to do it. Girls do not prefer dolls over trucks for
toys. Girls are pushed and encouraged to play with dolls as opposed to trucks. These things are not only
conditioned for in one generation, but the conditioning over many generations is passed along to the newest

We grow up into gender roles defined by our parents, teachers, television, acquaintances and friends. We
are not born with defined gender roles imprinted in our brain. We are born as human beings with basic
personality characteristics that are molded and shaped by reward, punishment and observation. So if
reward and observation are steered in one direction, as children we find ourselves following this facilitated
path. The development of the brain follows suit and the pseudo-scientists find size differences in particular
parts of the brain later in life which merely reflect the selective training of certain parts of the brain in one
gender or another. Programming children for “gender appropriate behaviors” starts from day one in society
with choosing colors for clothing and bedding, reaching to every other aspect of our lives and many
insensitive children go along with it without questioning. Sensitive children usually have a problem with it.
Like everything else that is unnatural sensitive kids tend to protest the gender exclusivity in their upbringing.
Even when they do not protest, they cannot be ok with it since it opposes their natural tendencies of
exploring every possibility before settling on a selected behavior that is in synchrony with their constitution.
When children are truly allowed by their parents and environment to explore all behavioral possibilities
without bias, the end result is many times a wonderful mix of conventional male and female “assigned”
behaviors. The end-result may also be a clear preference for conventional male behavior in boy or
conventional female behavior in a girl. The end-result may also be a clear preference for conventional male
behavior in a girl or a clear preference for conventional female behavior in a boy. The end-result is often
somewhere in between all that mix of possibilities, and would not that be wonderful if everyone is allowed
to be who she or he is without constraints or arbitrary conditioning.

When I hear someone asking, “is this normal?” I ask myself, who made this person an authority on normal.
Usually, there is someone who is always ready to define normal by exclusion. This behavior or that piece of
clothing or any other aspect of human life can be erratically attacked, usually by the insensitive majority, as
not normal only because they would not prefer to do it. Most people who venture into defining normal have
in my opinion the mental and emotional capacity of a speaking lizard. I say that since those who seem to
own the definition of normal typically cannot present any scientific or objective evidence to back their

Moreover, when I hear about all the studies that show that children need a mother and a father to grow up
into healthy and thriving adults, I ask myself, so what criteria was used to recruit the subjects in the
studies. Invariably the recruitment is based on genitals and not personality complex of an individual. Every
child needs a mother and a father to grow up. This is not a subject to be studied. It is the natural order.
However, the genital gender of the parent should not be a determining factor. Adults are individuals with
personalities that vary from the most conventional male behavior exclusively to the most conventional
female behavior exclusively. The possessor of such personality may be a male or a female. There are many
men who permanently display more or less conventional female behavior. There are also many women who
permanently display more or less conventional male behavior. Therefore two parents, a mother and a father,
can be two males [genitally] where one partner is displaying conventional female behavior while the other is
displaying conventional male behavior. The two parents can also be two females [genitally] where one
partner is displaying conventional female behavior while the other is displaying conventional male behavior.

In fact, people who conduct these aforementioned uninformed bogus studies should pay more attention
toward families where children are trapped within genitally male-female parents who both display female
behaviors or both display male behaviors. This is where the problem is and the deprivation is and not with
same sex or trans-gender couples. One day ignorance will give way to illumination.

There is growing evidence in the literature today that the brains of sensitive kids (boys and girls) show
substantial differences from the brains of insensitive kids (boys and girls). One main difference seems to be
in the proportion of gray matter over white matter. Sensitive kids seem to have more gray matter than
insensitive kids regardless of gender. Grey matter is the part of the brain that hosts the cell bodies of the
neurons. The white matter is the part that hosts the axonal connections between neurons. No one really
knows yet the significance of these findings and whether they follow or explain the personality spectrum or
not. However, not to be outdone, I will take a jab at it. Gray matter is involved with information processing.
White matter is involved with information transmission. Boys and girls with more gray matter [sensitive
kids] tend to process information thoroughly and transmit it more slowly and sparingly. Boys and girls with
more white matter [insensitive kids] tend to process information less thoroughly and to transmit it faster
and more frequently.

Dissecting the science behind the “topic”:

MALES BETTER: Spatial abilities including mental rotations, route learning, and visualization of spatial
FEMALES BETTER: Verbal skills including fluency, rate of speech acquisition, spelling, and grammar
MALES BETTER: Mathematical reasoning and problem solving        
FEMALES BETTER: Computational accuracy and procedural knowledge of arithmetic and mathematics
MALES BETTER: Gross motor skills that involve strength        
FEMALES BETTER: Fine motor skills and finger dexterity
FEMALES BETTER: Short term memory including memory for object locations

Courtesy Elizabeth Hampson: Sex Differences in Human Brain and Cognition: The influence of Sex Steroids
in Early and adult Life; in Behavioral Endocrinology, second edition, the MIT press (2002); Becker JB,
McCarthy MM, et al. (editors); P 580

This table sounds to me more like a bunch of urban myths than a table of scientific discoveries. Doctor
Hampson compiled this table. This poor woman took up the task of reviewing the literature on sex-based
differences between men and women. She has written her conclusions into articles and books. When I
stumbled on her work I had already done a good deal of searching on the subject. I was thrilled that
someone else had dedicated the time and effort to figure out the kinks of the topic. As I read through her
work, I found out that I was reading pages upon pages of beautifully written, meticulously described
nothingness. It was quite an experience reading the work of countless scientists over 150 years that cost
the taxpayers hundreds of millions summarized into nothing of value. Even if all the findings in this table
were 100% true, they still would not justify the presence of a “men’s” nature and a “women’s” nature.
These are at best such minor differences that would only say that men and women share the same nature
but are not completely identical in each and every aspect. I might be leaning to the side of the behaviorists
on this one. The behaviorists say that almost all non-reproductive sex based differences are a product of
upbringing and societal enforcement of gender roles.

In my opinion herein lies the role of an enlightened independent parent who does not succumb to tradition
and societal pressure. An enlightened parent will take it upon herself not to bias her sensitive offspring
toward any predetermined gender role. But she makes sure that her children are opened to all possibilities in
order for them to find out who they are and to adhere freely to their nature irrespective of glorified societal

Having said all that and having challenged maybe every glorified societal rule that we take for granted in
raising children, sex hormones are not without a role in development. There is persuasive evidence that:

1-        Testosterone may improve spatial learning. This relates to the orientation in space, three dimensional
thinking and sense of direction. This by no means implies that boys get these benefits exclusively. As you
might know girls and boys both have testosterone. Boys, on average have more testosterone than girls as
fetuses, in the first few months of life and as of puberty.

2-        Estrogen facilitates learning behavior. Estrogen seems to allow for more efficient connections
between neurons leading up to forming permanent memories of learned material. As you might know girls
and boys both have estrogen. Girls, on average have more estrogen than boys especially as of puberty.

3-        Estrogen also facilitates transmission of excitatory activity across nerves. This goes to improved
alertness and shortened reaction times. Boys not only have estrogen but also can make estrogen out of

The presence or absence of testosterone at critical times during pregnancy and shortly after birth leads to
masculinizing the reproductive system and the parts of the brain that regulate the reproductive system. I am
referring to the development of genitals and the control, by the brain, of sex hormone production later in life
starting with puberty.

If testosterone does not show up, then feminization of the reproductive system and reproductive behavior
happens. This process does not seem to need any real estrogen exposure. It only needs the absence of
testosterone. One may say that all fetuses start out feminine and later some become masculine upon
testosterone effects.

Organizational effects of sex hormones:

Studies in rodents and other animals have shown that sex hormones exert powerful effects during
pregnancy and shortly after birth on the brain. These effects early in life induce changes in the structure of
the brain to influence the development of specific functions. In a way sex hormones in many animal species
are able to induce the development of neural networks specialized for certain functions. The induced
development may include forming new neural connections or expanding existing connections or even
forming new bundles of neurons. This is a pretty exciting prospect of hormones influencing the ways by
which the brain develops and ultimately the ways by which we think and which areas in life is a growing
child likely to excel in. Some may go a step further to give parents a menu of paths in life to choose from
and then a specific hormone in a specific amount can be given to produce the required effect; only if the
animal studies prove to be true in humans!

As you might imagine, many scientists are trying to duplicate these findings in humans. At this time
however, there is a gap as big as the Pacific Ocean between the facts and the hype. The hype aside, there is
only limited evidence that the right amount of testosterone during pregnancy can enhance spatial learning as
discussed earlier. It is not known whether this effect is due to testosterone acting directly or through
conversion to estrogen. It is assumed that testosterone exerts it effects on the brain during pregnancy to
change the configuration by which neurons communicate and to add new neurons in certain areas in the
cerebral cortex responsible for spatial learning. This seems to give a slight advantage in this area to boys
over girls. There is not much more real evidence for other effects of sex hormones on the structural
development of the brain. Even in the area of spatial learning itself, no one has yet been able to actually
witness the influence of testosterone on the structural integrity of the human brain in a living embryo or
infant. The conclusions made so far are based solely on behavioral observations and some hormone

Since I am blessed with being able to look at the Pacific Ocean frequently, I like to dream some more. I do
believe that we will be able to find out over the next couple of generations that sex hormones including
progesterone, estrogen and testosterone make their stamp on the structural integrity of the human brain
starting in the womb onwards. I further believe that these influences may not be what scientists hope they
will be. This means that hormonal influences may not direct us into finding that girls and boys have
separate natures but that girls and boys share the same nature with minor variability. Be that as it may, for
the time being these organizational effects of hormones seem limited in scope to warrant any scientific
distinction between boys’ and girls’ nature.

It is noteworthy that all the evidence we are discussing is based on the effects of the natural human
hormones on the brain. Synthetic hormones like steroids and other xeno-chemicals used in birth control and
assisted reproductive technologies may prove to have profound untoward influences on changing the wiring
of the brain of mother and child at any age, especially early in life. Only if we can get pharmaceutical
companies to investigate their products for such influences! These synthetic hormones exert effects that
are many folds more powerful than human hormones. In addition, many synthetic hormones operate in
ways that may be completely different from the way human hormones operate. Recently, some enlightened
doctors have realized the detrimental effects of synthetic hormones on embryos and have stopped
prescribing such chemicals to pregnant women. On the other hand, there is a scary growing trend to
prescribe synthetic steroids to children with asthma, allergies, inflammatory conditions and infectious
problems among a variety of other reasons. This bone-chilling trend may be the greatest experiment any
generation has been subjected to since diethylstilbestrol (DES) was given to pregnant women in the fifties.

Activational effects of hormones over mental processes and behavior:

The activational effects of hormones refer to the ability of hormones to sharpen or alternatively dull certain
behaviors. This influence is assumed to reflect the impact of hormones on the degree of activity of certain
areas in the brain. From a reproductive perspective women do not possess any physical changes, which
inform their partners of the appropriate times for procreation. In many species in the animal kingdom the
female displays obvious signs of receptivity to sexual intercourse. For example, when a female rat is
ovulating, it contorts her body in a way to expose her genitals to make it easier for the male rat to mount
her for the purpose of procreation. In some bird species, the male bird knows it is getting lucky, when the
female allows him to groom her neck feathers with his beak extensively. There are many more signs and
signals animals use to ensure propagation of the species.

Humans do not display any of these obvious physical signals. However, human females have certain
instinctual behaviors meant to explain to their male partners the appropriate times for sexual activity. Some
studies have found that women in relationships or in courting may display more agreeable, less articulate
behavior around mid-cycle [time of egg release]. This is explained as an effort on the side of the female to
keep her male partner close, content and feeling in control in order to fulfill the instinctive drive for
procreation. This display on a woman’s side is the result of a combination of positive mood, somewhat
submissive and territorial behavior. This behavioral complex is thought of as related to increase in estrogen
around days 12-15 of the menstrual cycle. In contrast, after this fertile phase is over, women tend to be
more dominant and verbally and emotionally articulate while simultaneously showing faster response time
during the third week and leading up to the end of the cycle. This is said to be due to the effects of
increasing progesterone [and possibly serotonin] during the third and fourth weeks of the cycle. In this
discussion we refer to the first day of the menstrual period as day one of the menstrual cycle that lasts
hypothetically 28 days.

The effects described above are usually apparent in the relationship between two partners. They may not be
visible to or extend to anyone else including close friends and family. These behavioral changes are adaptive
and directed toward a male partner or a potential male partner. These behavioral changes are not related to
most other aspects of a woman’s social behavior.

For single women, not in relationships or courtship, their sense of smell [and sight] is heightened around
mid-cycle in an effort to have the best discrimination powers over choosing the right mate. These effects
are also said to be due to increasing estrogen around days 12-15 of cycle.

Toward the end of a menstrual cycle that does not culminate in pregnancy there has been some observed
clumsiness in some women. When the menstrual period is about to begin and for the duration of the period,
some women show mental and physical clumsiness. This could be most apparent in dexterity and
coordinating muscular activities around that time. This is a time in the cycle when both estrogen and
progesterone are dropping to their lowest levels of the month. Cycling women are said to be especially
vulnerable to physical accidents and injuries around this time of the month.

Single women and women in relationships share all the behavioral descriptions made so far in this section.
However, the author is emphasizing different behavioral attributes for different groups based on situational

In men, there seems to be some relationship between testosterone and spatial abilities [sense of direction]
and aggressive pursuit of goals.

The activational effects of hormones on cognition and behavior are not linear effects. The effects happen
only within a narrow window of exposure to the hormone in question. For example, if testosterone
improves or facilitates aggressive pursuit of goals, it does not mean that injecting someone with a
humongous dose of testosterone makes them even more aggressive in pursuing goals. On the contrary, the
initial improvement in testosterone from below normal levels to normal levels has this effect while
increasing testosterone further to above the average level of healthy men does not further accentuate the
aggressive pursuit. It follows that all the presented research conclusions on the activational effects of
hormones on behavior are done in light of what average concentrations of hormones would do.

Another example that may shed more light on this issue is that of testosterone and libido. It is quite popular
to think that testosterone improves sex drive in men and women. Many doctors are carried away with this
concept and give testosterone in excessive amounts thinking that more testosterone means further
improvement in libido. Nirvana is just one doctor’s visit away! In fact, this hardly ever works. Improving
testosterone from below normal limit to the lowest 20% of the average range gives all the benefits of
testosterone can have over sex drive, erotic thinking and clitoral/penal stimulation. Any increase in
testosterone over and above the first 20% of the average range does not have any further influence on sex
drive. Even when the testosterone concentrations are increased several folds above the average range, the
effect observed in the lowest 20% of the reference range remains constant and does not increase any
further. However, when that happens behavioral aggressiveness often leading to marital discourse often

In conclusion, there is some evidence for the presence of activational effects of hormones on human
behavior. These effects are by and large for reproductive purposes. Non-reproductive effects of hormones
on behavior seem to be peripheral and exert only limited influence in the bigger scheme of things. All the
efforts over many years have not yielded any major breakthroughs that could push one to re-think human
nature based on gender or hormones. Contrary to popular belief one’s personality is not decided by the type
of genitalia they have or the types of hormones flowing in their body. Forming one’s personality is a much
wider and complex subject in which sex hormones are significant but minor players.

Author: Rami Serhan, MD
Medical consultant
Sovereign Research
(206) 659-1ASD (273)

Note: this article is an excerpt of the upcoming book, “PSYCHE-SMART AUTISM”.
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