[Paleopsych] Newsweek: The Truth About Gender

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Wed Apr 20 21:49:04 UTC 2005

Here are eight more articles, bringing it up to my daily maximum of ten. I 
think they are all science related.


The rift between the sexes just got a whole lot bigger. A new study has
found that women and men differ genetically almost as much as humans differ
from chimpanzees.

By Fred Guterl
Newsweek International

March 28 issue - When it comes to gender differences, everybody's an expert.
But George Lazarus is a bit more expert than most. Although he doesn't study
the subject formally, as a pediatrician in New York City he sees a lot of
children, who are, after all, far better than adults at expressing their
essential natures. One girl's parents, for instance, set out to raise her
without "gender bias" that might hinder her success later in life. When she
turned 3, they eschewed dolls and gave her toy trucks instead. The girl went
off to her bedroom to play. When the parents checked up on her, they found
her tucking the trucks in bed for the night. "Shhhh!" she said. "They're

It's a story that Larry Summers, the beleaguered president of Harvard
University, might appreciate. Summers caused a firestorm when he suggested
several weeks ago that differences in "intrinsic aptitude" might be the
principal reason the university has fewer females in the sciences and
engineering than males; he lost a vote of no confidence in the Faculty of
Arts and Sciences last week. Summers may be guilty of social indiscretion,
but is he wrong, scientifically speaking? Does biology play no significant
role in determining the talents and behaviors of men and women?

Considering the importance of the question, few studies have addressed it.
Nevertheless, in recent years, scientists have been finding that the
biological rift between men and women is larger than previously thought. To
an extent few would have believed a few years ago, the center of gravity of
scientific opinion on gender has begun to shift-and it's making everybody

One of the most intriguing findings concerns the genetic differences between
men and women. A study published last week in the journal Nature puts this
difference at about 1 percent. Considering that the genetic makeup of
chimpanzees and humans differs by only 1.5 percent, this is significant.
"You could say that there are two human genomes, one for men and one for
women," says Huntington Willard, a geneticist at Duke University and
coauthor of the article. The study did not spell out exactly which genes do
what. Rather, its results were like looking at the innards of two almost
identical clocks and finding that in fact each has an altogether different
arrangement of gears.

Scientists have long known that a person's sex is determined by two
chromosomes, or bundles of genes-a woman inherits two X chromosomes, one
from each parent, while a man inherits an X from -mom and a Y from dad. For
the past 40 years, scientists have thought that the extra X chromosome in
females shuts down, while the other works alone. The Nature study, though,
found that about 20 percent of the genes on the duplicate X chromosome-about
200 genes in all-remain active. Men, by contrast, have only one active X
chromosome (plus a few genes on the puny Y chromosome). Not only are women
genetically more complex and varied than men, they differ widely from one

Only a few years ago, scientists used to think that hormones were the
primary mechanism of gender. The Y chromosome was assumed to do little but
trigger a cascade of genes scattered among the other 22 human chromosomes,
which ends with the production of the testes. Hormones still do a lot of the
heavy lifting-with one crucial difference. Scientists have found that while
hormones wreak havoc on just about every part of adolescent physiology, they
have almost no effect on brain development. Studies of girls born in
triplets, sandwiched in the womb between two brothers, show that although
the girls acquire some masculine traits due to a heavier-than-normal dose of
testosterone, their brains are unaffected. Genetic variations, on the other
hand, have a huge impact on the brain. Down-syndrome boys, born with extra
genes from chromosome 21, are cognitively impaired. When it comes to the
brain, genes rule.

How, then, do female brains differ from male brains? Scientists are only
beginning to address this question. So far, it seems clear that men and
women think differently in significant ways. When navigating a maze, men
tend to think spatially (go north for 200 meters and then turn left), while
women look for landmarks. Brain scans of men and women engaged in rhyming
words show that they use different brain circuits to perform the same task.
Women also have 15 to 20 percent more gray matter (ordinary neurons) than
men. And their white matter (long neurons that help the brain distribute its
processing tasks) is concentrated at the juncture between the brain's left
and right hemispheres, and may help women use both sides of their brain for
language-related tasks.

There's also anecdotal evidence. On the Scholastic Aptitude Test, a college
entry exam, women consistently score lower than men on the mathematics
portion. (They do better on language skills, but still score slightly lower
than men.) And then there are things like the makeup of the Harvard faculty.
Such real-world evidence, of course, doesn't tell us what is cause and what
is effect. To what extent does environment-education, upbringing, nutrition,
exposure to stress, chemicals and so forth-play a role? Are boys slower to
develop verbal skills because of their genes, or because they spend more
time playing with trucks than talking with their friends?

Is Larry Summers right or wrong? At the moment, there's too little data to
say. Even when scientists eventually come to understand the genetic
clockwork, there's a good chance the answer won't be quite so simplistic.
Individuals vary so widely in ability that any aggregate difference between
men and women won't likely affect the ambitions of any aspiring scientist or
playwright. Besides, genes can confer both advantages and disadvantages. The
chances are pretty good that we haven't yet measured them all.

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