Women and men are different. Not only do
we look different, but we act differently and feel differently.
This is not a new revelation. But for the last 30 years the differences
between the sexes has been attributed to social learning.
According to this theory, we really dont have any sexual
identity when were born. A child is taught what it means
to be female or male, and what we consider feminine behavior
or masculine behavior depends on the culture. If a girl was taught
that its feminine to play with toy guns and do a lot of
wrestling, she would, and shed enjoy it just as much as
boys do. The theory says that the differences between the sexes
are caused by socialization by what we learned from parents,
teachers, television, and our peers. The theory says we learned
what is feminine or masculine, and thats why women and
men tend to behave and feel differently.
As a matter of fact, the socialization
theory is so widespread, for many people it isnt a theory
at all, its a self-evident truth.
But lately, this truth is being
shaken by some very solid research from the fields of biology,
genetics, neurology and endocrinology. Scientists all over the
world are accumulating research data indicating that many of
the differences between the sexes are biological and inborn,
and some are not much affected by learning.
Thats not to say socialization has
no influence. The ability to become socialized the ability
and desire to learn from our own culture is itself a genetically-created
trait, and a powerful one at that. Obviously socialization has
an influence. But apparently there are some things out of reach
of social learning some feminine or masculine behavior
that cannot be unlearned or overridden.
You might legitimately ask, What
difference does it make? We can see the sexes are different;
who cares what the exact cause of it is?
Thats a good question. Political
issues aside, the answer is: Itll make a difference to
you in your relationship with your mate. The differences between
the sexes are often a cause of conflict or an underlying source
of conflict between a man and a woman.
Most of us believe these differences are
learned. And of course, if your mate learned it, your
mate can (damn well) unlearn it! Right?
BUT if some of those differences
were produced by your mates biology, and you were convinced
no amount of effort could change it, guess what? Youd find
it easier to accept your mate for what she or he is, and that
would have a significant impact on the quality of your relationship.
You may still dislike some of your mates
characteristics, but you would stop frustrating yourself with
unfulfilled expectations. And you would learn to work around
Look at it this way: If your mate was nearsighted,
and you thought nearsightedness was a learned condition,
it might become a point of friction in your relationship. Maybe
youre always on your mates back when s/he is driving,
for example, because it seems to you s/he is just not paying
If you then discovered that the nearsightedness
was something your mate was born with and that there wasnt
anything s/he can learn to make it better, heres
what would happen: 1) your expectations would become more realistic
(more fitting given the reality), 2) you would be less frustrated,
3) youd become more forgiving and understanding, 4) you
would have less animosity toward your mate, 5) you would start
thinking of ways the two of you could work around your situation
rather than simply railing against it (maybe buy some spectacles,
for example, or you could do more of the driving).
Thats what I want to accomplish with
this booklet: I hope to share enough of the enormous amount of
research on this subject that your expectations of your mate
become more realistic. With more realistic expectations, you
can realistically expect to be more satisfied with your mate.
Some of the conflict will disappear from your relationship, and
you will find new ways of appreciating each other.
As long as you hold out hope that someday
your mate will change, you will be frustrated and disappointed.
But if you accept that the differences are irreversible (short
of surgery or hormone supplementation) you can begin to work
with the reality of the situation instead of banging your
head against a wall trying to apply the Strictly-Socialization
Theory a theory whose time has come and gone.
In the Beginning
It all begins at conception. The individual
sperm cell that enters the egg determines the sex of the fetus.
Female sperm carry more information (the information required
for the complex processes of pregnancy and birth) and are therefore
heavier than sperm carrying male chromosomes. Because it is heavier,
a sperm carrying female genes moves slower than a sperm carrying
male genes. So sperm carrying male genes get there quicker and
are more likely to conceive. 125 boys are conceived for every
This difference, right out of the chute,
so to speak, is of course not the result of socialization.
After conception, females mature faster
and are born with a 4 to 6 week developmental head-start over
males. This has nothing to do with learning or socialization,
either. It is a genetic difference.
About one or two months after conception,
if the fetus has an XX chromosome, it begins to produce large
amounts of estrogen. If the fetus has an XY chromosome, it begins
to produce large amounts of testosterone. These hormones organize
the development of not only the body, but also the brain.
Later, the hormone levels go way down,
but then increase again at puberty, and remain high into adulthood,
activating specific receptor sites in the brain and
A receptor site in a cell is like a button.
The only thing thatll push that button is a specific hormone.
For example, there is a molecule very much like testosterone
(human male hormone) circulating in the blood of male apes, male
birds, male crabs, male fish just about every male on
the planet and this molecule activates certain behaviors
in these animals: strutting, defending territory, displaying
There are parts of the animals brain
responsible for each of those behaviors. There are receptor sites
in those parts of the brain, activated by the male hormone. All
of those male-only behaviors are activated by the same hormone.
For example, among certain kinds of songbirds,
the male sings but the female does not sing. Inject the female
with testosterone, however, and she begins to sing. The receptor
sites in the brain are only activated, in this case, by the male
If you castrate a male Japanese quail,
it will stop copulating and crowing. By castration, you have
stopped the production of male hormones. All those receptor-sites
stop being activated. Give him an injection of male hormone,
and hes back to crowing and copulating.
Male fiddler crabs normally have one huge
claw and one normal sized one. But castrate one while he is young,
and his claws are both normal size as an adult, just like a female.
Back near the beginning of the evolution
of animals, DNA divided itself into two sexes, and the development
of the male and female sex organs were triggered by a testosterone-like
molecule and an estrogen-like molecule.
Its a good adaptation. Its
a clean way to create the necessary differences in the sexes.
Over time, more and more adaptations were added to each sex.
The two sexes of a single species could now evolve differently,
because any adaptation could be triggered by the male or female
hormone. So if it produced more offspring to have a wider pelvis
in the female, the adaptation could be added and triggered
only by estrogen. And if it wasnt adaptable for males,
they could stay as they were.
Human males dont have claws and we
dont crow. We may strut a little, but not much. We do have
testosterone, and women do have estrogen, however. As a fetus,
the blood levels of these hormones are up to four times the level
they will be in childhood. Why? Because there are basic biological
differences being hardwired during the fetuss development,
making the sexes fundamentally and unalterably different for
the rest of their lives.
The Human Species
In people, these differences show up in
hundreds of different ways. For example, June Reinisch, a developmental
psychologist, studied 4,653 infants and found that girls sat
up without support earlier than boys, and boys crawl earlier
than girls, but then crawl for a longer period of time before
they learn to walk. The brains of boys mature more slowly, especially
the frontal lobes (responsible, in part, for handling cognitive
and social functions).
Keep in mind that these are all averages.
Individuals vary wildly. But generalizations can be made and
they will be true for most people. You can easily say, without
argument from most people, that men are taller than women and
that women have less body hair than men. Now of course, there
are some women who are taller than some men, and there are some
men who have less body hair than some women, but by and large,
the differences hold true.
In other words, the generalization is very
likely true in your relationship.
It is also generally true that women have
better nighttime vision, more flexible joints, and a better oxygen
supply to the brain. A womans skin bruises more easily
than a mans, and her sweat glands and fat cells are more
evenly distributed. She tends to perspire more heavily under
her arms, while he perspires more heavily on his chest.
Men have thicker skin, fewer nerve endings
on the surface of the skin, a thicker skull, a more slanted forehead
and heavier brow ridges (to support larger jaw muscles). Men
have tighter joints, better daytime vision and more acute depth
Of course, none of these differences are the result of socialization.
Women have one million fewer red blood
cells in each drop of blood than men. Yes, you read that correctly:
Take one drop of male blood and one drop of female blood and
youll find a million more red blood cells in the mans.
A mans blood also coagulates faster than a womans.
We come from a long line of hunter-gatherers,
and some of these sex differences must have come about because
in all hunter-gatherer societies on record (except for one: the
Agta of the Philippines), there is a division of labor by sex.
Men did the hunting, women did the gathering.
Some of the earliest sex-difference studies
showed that men are better at hitting targets with projectiles
than women. And in all the research since then, this has been
one of the most consistent findings. Okay, said some researchers,
it makes sense that men would be superior at hunting tasks
superiorities like being able to hit a target with a projectile.
Fine, they said. Good. But wouldnt gatherers also
develop some superiorities? Like being able to locate berry bushes
and tuber patches and nut trees?
So the researchers set up some experiments
to find out. In one experiment, a table was piled with objects.
A comb, a dishrag, a hammer, a typewriter, a book, etc.
one big jumbled pile of different objects. A man or woman was
brought into the room and told to look at the pile for some specified
length of time, say, two minutes. Then the man or woman was escorted
out of the room. Then the researchers would either remove an
object or move it to a different location in the pile.
The subjects were brought back in and asked
if the pile looked any different. Sure enough, women are better
able to detect a change in location than men. Women have a superior
ability to remember the locations of objects.
In fact, women are better at almost all
forms of perception: better at hearing small changes in tone
of voice and volume, have a better perception of high-sound frequencies,
a better ability to distinguish between different tastes, more
nerve endings in their skin (and therefore a greater sensitivity
to touch), are better at seeing in the dark, and have better
Men have better depth perception and can
see better in bright light. The only auditory superiority men
have is in distinguishing animal sounds. A womans chances
are one in fifty thousand of being color blind; a man has a chance
of one in twenty-five.
Estrogen activates the olfactory receptors,
and since women have far more estrogen than men, womens
sense of smell is better. Women can detect the scent of musk
better than any other odor.
Her estrogen levels vary over the course
of a month, and during ovulation, when her estrogen level peaks,
she can detect the scent of musk 100 to 1000 times more keenly
than during menstruation.
Women notice more. In one experiment, subjects
were told the researchers werent ready to start yet and
asked each one (one at a time) to wait in a small room for a
few minutes. Afterward, the subjects were asked what they could
recall from the room they were in. That was the whole experiment.
The women remembered an incredible (to me, a male) amount of
detail. They would say things like, There was a shelf against
the wall crowded with things. There was an open pack of Wrigglys
gum, a book on Greek history, a black sock, a worn out tan colored
knapsack, etc. Rich detail. When they asked the men the
same question, they apparently hadnt paid much attention:
It seems to me there was a shelf in there with some stuff
on it. There was a pack of gum...some clothes or something...
Klassy (my wife) used to tease me about
not noticing things, so I was determined to pay attention. One
day, feeling victorious, I said, Hey! You moved that picture.
It used to be over here.
Youre right, she said,
I did move the picture...three months ago!
Men spend more time in shallow sleep as
they get older, but aging doesnt affect womens sleep
There is an enzyme in the stomach that
breaks down alcohol before it reaches the bloodstream. The enzymes
in womens stomachs break down less than one fourth as much
alcohol as the enzymes in mens stomachs, allowing more
pure alcohol to enter her bloodstream.
Migraines affect 4 times as many women
as men. Women suffer from more aches and pains in general than
men. Women feel some sort of discomfort 43% of the time, men
28% of the time. And men find it twice as difficult to tolerate
the same amount of chronic pain a woman can tolerate.
Most men put their pants on left leg first;
women usually put their pants on right leg first.
According to Dr. Brian Sietsema, the Pronunciation
Editor of Merriam-Webster, men and women pronounce the TH sound
(as in the word think) differently. Men pronounce
it with the tongue slightly behind the upper teeth,
he says, and women with the tongue between the teeth.
Men tend to call each other by a word other
than the persons name: dude, man, etc., and women tend
to use the persons name.
Women have better coordination in their
fingers. You can tell a womans handwriting from a mans
because her's shows more control.
Again, there are variations, but in general
each of these differences are likely to be true between you and
your mate. Likely. Not absolutely.
During an argument between husband and
wife, her blood pressure rises, on average, 6%, whereas his rises
14%. His blood pressure rises more than twice what hers does.
Logically, youd think itd be just the opposite because
she is potentially in more physical danger.
But the differences go beyond logic. They
are differences built into our brains and bodies, and the only
criteria for the choosing was survival. If a trait survived and
had offspring, that particular pattern of DNA went on to have
more offspring. If it didnt have any offspring, it didnt
pass its genes to us. Apparently there was some advantage to
having calm women and reactive men. Although those traits may
no longer be an advantage, were stuck with the biology
Men die sooner or more often in 57 of the
64 major causes of death. In fact, says, Deborah Wingard, an
epidemiologist at the University of California, San Diego, If
you look at the top ten or twelve causes of death, every single
one kills more men.
Denying the biological differences between
men and women can be dangerous. Theres a drug prescribed
for high blood pressure called Propanolol. Recently it has been
found that Propanolol is broken down far more slowly in womens
bodies than mens. Doctors had to lower the dosage for women
so they werent continually overdosed.
A hormone called DHEAS reduces the risk
of heart disease in men and contributes to their longevity. But
this hormone had the opposite effect on women (it increases
their risk of heart disease).
Twice as many women experience depression
than men, and women take 83% of all antidepressants. But the
studies on these drugs were done on men. Naturally, if the differences
in the sexes are only caused by socialization, then a drug that
works for men should work just as well for women. Of course.
Thats the politically correct view. But Jean Hamilton,
M.D., a researcher from Duke University, found that womens
menstrual cycles affected their reaction to psychotropic drugs
(like antidepressants), in some cases causing serious trouble.
For years, doctors told us the warning
signs of a heart attack: A dull pain in the center of the chest
and/or pain down the left arm. Recent research has found, however,
that those are mens symptoms. Women often experience
pain in the back, neck or jaw, or they have nausea, or light-headedness,
and often no chest pain. I wonder how many women have had heart
attacks because they ignored these symptoms? Assuming that women
and men are alike caused deaths.
The sexes are not the same. They
react to drugs differently. They show different symptoms. It
is not simply a matter of opinion. It is not just a theoretical
issue. It is not merely an interesting subject of intellectual
debate. An ignorance of the differences can kill a person.
The differences go on and on. And all were
created by the hormone that dominated in the womb: estrogen or
In women, there are fibers that hold skin
to the muscles in parallel cords. This causes the fat in between
to bulge, producing whats called cellulite. In men, the
fat is held in place by a dense mesh of fibers, making cellulite
much less likely.
Men tend to store body fat around their
waist, which produces more cholesterol and triglycerides than
storing it in the butt and thighs, where women tend to store
most of their fat. One of the reasons men are more susceptible
to atherosclerosis and heart disease is the different way they
store fat. Fat on the waist is easier to burn. Fat on thighs
is more resistant. Its safety fat. Women who had this fat
in times gone by had more babies survive in times of scarcity.
Female mammals (including humans) are able to withstand food
deprivation for a longer period of time before dying.
A womans muscles are less striated,
making them weaker but more efficient at burning blood sugar.
A man has one and a half times as much muscle and bone as a woman,
and half as much fat.
Estrogen affects how much fat a person
wants to eat. Humans and other animals have a substance called
galanin in their bloodstreams. Galanin produces a desire to eat
fat, and makes the fat consumed more likely to be converted to
Sarah Lebowitz, in her experiments at Rockefeller
University, found that if you give a cow an extra shot of galanin,
the cow eats more fat. Lebowitz has also found a molecule
called M40 that blocks the production of galanin. When
she administered M40 to animals, they had no taste for fat at
all. They ate protein and carbohydrates, but showed no interest
in eating fat.
Lebowitz discovered two things that stimulate
the human body to produce more galanin. One is the by-products
of burning body fat. This makes sense: Your body notices youve
burned off some fat, and it stimulates your appetite for fat
so you can replace what youve burned. The other thing that
stimulates the production of galanin is estrogen.
Women have more estrogen and more body
fat. This is genetic; not subject to change by socialization.
We may or may not like it. DNA doesnt care about our personal,
social or political ideals.
A woman has more fat covering her entire
body, giving her greater protection against the cold and more
buoyancy in the water.
Do you remember the couple who got lost
in a snow storm, took the wrong road and ran out of gas? They
sat in the car for a day or so and then realized they better
find help no one had driven by in two days.
They got out and started walking. They
had no food. They had their infant with them. Finally, they realized
they were headed in the wrong direction. They decided that the
mother and baby should hole themselves up in a tiny cave and
the husband should go back the way they came and find help.
He walked for days and finally found a
road and got help. They found his wife and child in good health.
Days without food, in freezing weather, and they were fine. The
baby was as healthy as could be. Through lactation, using the
extra fat on the mothers body, the baby survived.
Our ancestors went through similar adverse
conditions many times: Famines, terrible weather, exposure, epidemics,
bad water, you name it. Lots of them didnt survive. Those
whose children survived were our ancestors. Our bodies are the
design that can survive extreme conditions.
Some important features that helped those
offspring (our ancestors) survive were certain differences between
males and females. And those differences are deep and extensive.
At one time differences between the sexes
were used to prove that men are the superior sex. Because of
this, during the womens movement it became unfashionable
and even rude to discover or point out these differences. But
it is impossible to say which sex is superior by studying the
differences. Each sex has its own strengths and weaknesses. Neither
is superior. Being physically bigger is usually better
in a wrestling match, but what good does it do if the task is
nursing a child or locating a berry bush? Or creating a satisfying
relationship with another human being? Or swimming the English
In 1926 Gertrude Ederle attempted to swim
the English Channel, a feat no woman had ever attempted. A writer
for a London newspaper was so sure she wouldnt make it,
he wrote an editorial before she started saying that her failure
to cross the channel only showed that women should not attempt
to enter competitive athletics because they were so obviously
physically inferior. But Gertrude Ederle not only made it across
the Channel, she broke the existing mens record by two
hours! The world record is still held by a woman. Theres
no way men can compete women have superior biology for
The London paper went to press before the
editorial could be withdrawn, and the editor had to eat the crow
he completely deserved.
Lets stop thinking in terms of a
superior sex. Its like asking, Which is superior,
a sponge or a knife? It depends entirely what you are trying
to do. Lets focus instead on what we can do together. We
can share out strengths with each other and as a unit become
greater than the sum of our parts.
So far Ive talked about some of the
physical differences between the sexes, because I wanted to give
you an idea of how pervasive the differences are. Were
not talking about a few trivial differences in genital structure.
Women and men are different to the bone (literally). When you
realize that even our red-blood count is different, it becomes
easier to accept that some of the more subtle differences might
also be built-in and less subject to change than you thought.
Lets look at one of the more subtle
differences now a difference that can significantly affect
your relationship with your mate.
to part two