An Interesting Article

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Is sexual identity hard-wired by genes?
Genetics may explain male-female differences, scientists say
Updated: 6:49 p.m. ET Oct. 31, 2003LOS ANGELES - Sexual identity is wired
into the genes, which discounts the concept that homosexuality and
transgender sexuality are a choice, California researchers reported on
Monday.

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“Our findings may help answer an important question — why do we feel male or
female?” Dr. Eric Vilain, a genetics professor at the University of
California, Los Angeles School of Medicine, said in a statement. “Sexual
identity is rooted in every person’s biology before birth and springs from a
variation in our individual genome.”

His team has identified 54 genes in mice that may explain why male and
female brains look and function differently.

Since the 1970s, scientists have believed that estrogen and testosterone
were wholly responsible for sexually organizing the brain. Recent evidence,
however, indicates that hormones cannot explain everything about the sexual
differences between male and female brains.

Published in the latest edition of the journal Molecular Brain Research, the
UCLA discovery may also offer physicians an improved tool for gender
assignment of babies born with ambiguous genitalia.

Mild cases of malformed genitalia occur in 1 percent of all births — about 3
million cases. More severe cases — where doctors can’t inform parents
whether they had a boy or girl — occur in one in 3,000 births.

“If physicians could predict the gender of newborns with ambiguous genitalia
at birth, we would make less mistakes in gender assignment,” Vilain said.

Using two genetic testing methods, the researchers compared the production
of genes in male and female brains in embryonic mice — long before the
animals developed sex organs.

They found 54 genes produced in different amounts in male and female mouse
brains, prior to hormonal influence. Eighteen of the genes were produced at
higher levels in the male brains; 36 were produced at higher levels in the
female brains.

“We discovered that the male and female brains differed in many measurable
ways, including anatomy and function.” Vilain said.

For example, the two hemispheres of the brain appeared more symmetrical in
females than in males. According to Vilain, the symmetry may improve
communication between both sides of the brain, leading to enhanced verbal
expressiveness in females.

“This anatomical difference may explain why women can sometimes articulate
their feelings more easily than men,” he said.

The scientists plan to conduct further studies to determine the specific
role for each of the 54 genes they identified.

“Our findings may explain why we feel male or female, regardless of our
actual anatomy,” said Vilain. “These discoveries lend credence to the idea
that being transgender —- feeling that one has been born into the body of
the wrong sex — is a state of mind.”

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