Some of you people are laughable! Not only are you laughable...but exactly the type of people that perpetuate hate and ignorance! Homosexuality is a
crossing of...for lack of better terms, the wiring in the brain and hormonal imbalances....science is finally discovering this.....so no YOUR THE ONES
WRONG!
Biology behind homosexuality in sheep, study confirms
OHSU researchers show brain anatomy, hormone production may be cause
PORTLAND, Ore. � Researchers in the Oregon Health & Science University School of Medicine have confirmed that a male sheep's preference for same-sex
partners has biological underpinnings.
A study published in the February issue of the journal Endocrinology demonstrates that not only are certain groups of cells different between genders
in a part of the sheep brain controlling sexual behavior, but brain anatomy and hormone production may determine whether adult rams prefer other rams
over ewes.
"This particular study, along with others, strongly suggests that sexual preference is biologically determined in animals, and possibly in humans,"
said the study's lead author, Charles E. Roselli, Ph.D., professor in the Department of Physiology and Pharmacology, OHSU School of Medicine. "The
hope is that the study of these brain differences will provide clues to the processes involved in the development and regulation of heterosexual, as
well as homosexual, behavior."
The results lend credence to previous studies in humans that described anatomical differences between the brains of heterosexual men and homosexual
men, as well as sexually unique versions of the same cluster of brain cells in males and females.
"Same-sex attraction is widespread across many different species." said Roselli, whose laboratory collaborated with the Department of Animal
Sciences at Oregon State University and the USDA Agricultural Research Service's U.S. Sheep Experiment Station in Dubois, Idaho.
Kay Larkin, Ph.D., an OHSU electron microscopist who performed laboratory analysis for the study, said scientists now have a marker that points to
whether a ram may prefer other rams over ewes.
"There's a difference in the brain that is correlated with partner preference rather than gender of the animal you're looking at," she said.
About 8 percent of domestic rams display preferences for other males as sexual partners. Scientists don't believe it's related to dominance or flock
hierarchy; rather, their typical motor pattern for intercourse is merely directed at rams instead of ewes.
"They're one of the few species that have been systematically studied, so we're able to do very careful and controlled experiments on sheep,"
Roselli said. "We used rams that had consistently shown exclusive sexual preference for other rams when they were given a choice between rams and
ewes."
The study examined 27 adult, 4-year-old sheep of mixed Western breeds reared at the U.S. Sheep Experiment Station. They included eight male sheep
exhibiting a female mate preference � female-oriented rams � nine male-oriented rams and 10 ewes.
OHSU researchers discovered an irregularly shaped, densely packed cluster of nerve cells in the hypothalamus of the sheep brain, which they named the
ovine sexually dimorphic nucleus or oSDN because it is a different size in rams than in ewes. The hypothalamus is the part of the brain that controls
metabolic activities and reproductive functions.
The oSDN in rams that preferred females was "significantly" larger and contained more neurons than in male-oriented rams and ewes. In addition, the
oSDN of the female-oriented rams expressed higher levels of aromatase, a substance that converts testosterone to estradiol so the androgen hormone can
facilitate typical male sexual behaviors. Aromatase expression was no different between male-oriented rams and ewes.
The study was the first to demonstrate an association between natural variations in sexual partner preferences and brain structure in nonhuman
animals.
The Endocrinology study is part of a five-year, OHSU-led effort funded through 2008 by the National Center for Research Resources, a component of the
National Institutes of Health. Scientists will work to further characterize the rams' behavior and study when during development these differences
arise. "We do have some evidence the nucleus is sexually dimorphic in late gestation," Roselli said.
They would also like to know whether sexual preferences can be altered by manipulating the prenatal hormone environment, such as by using drugs to
prevent the actions of androgen in the fetal sheep brain.
In collaboration with geneticists at UCLA, Roselli has begun to study possible differences in gene expression between brains of male-oriented and
female-oriented rams.
www.ohsu.edu...
homepages.inf.ed.ac.uk...
Research shows the brains of homosexuals are structurally different
from heterosexuals, which could suggest that the homosexual tendency
is imprinted in the brain from birth. So it is not necessarily a
psychological condition, nor a religious one. Since homosexually has
been around since...well..homo sapiens, this makes more since with the
real world as well.
Simon LeVay observed that INAH3 was more than twice as large in the
men as in the women. But INAH3 was also between two and three fumes
larger in the straight men than in the gay men. In some gay men, as in
the example shown at the top of the opposite page, the cell group was
altogether absent. Statistical analysis indicated that the probability
of this result's being attributed to chance was about one in 1,000. In
fact, there was no significant difference between volumes of INAH3 in
the gay men and in the women. So the investigation suggested a
dimorphism related to male sexual orientation about as great as that
related to sex.
One other feature in brains that is related to sexual orientation has
been reported by Allen and Gorski. They found that the anterior
commissure, a bundle of fibers running across the midline of the
brain, is smallest in heterosexual men, larger in women and largest in
gay men. After correcting for overall brain size, the anterior
commissure in women and in gay men were comparable in size.
At first glance, the very notion of gay genes might seem absurd. How
could genes that draw men or women to members of the same sex survive
the Darwinian screening for reproductive fitness? Surely the parents
of most gay men and lesbians are heterosexual? In view of such
apparent incongruities, research focuses on genes that sway rather
than determine sexual orientation. The two main approaches to seeking
such genes are twin and family studies and DNA linkage analysis.
Twin and family tree studies are based on the principle that
genetically influenced traits run in families. The first modern study
on the patterns of homosexuality within families was published in 1985
by Richard C. Pillard and James D. Weinrich of Boston University.
Since then, five other systematic studies on the twins and siblings of
gay men and lesbians have been reported.
The pooled data for men show that about 57 percent of identical twins,
24 percent of fraternal twins and 13 percent of brothers of gay men
are also gay. For women, approximately 50 percent of identical twins,
16 percent of fraternal twins and 13 percent of sisters of lesbians
are also lesbian. When these data are compared with baseline rates of
homosexuality, a good amount of family clustering of sexual
orientation becomes evident for both sexes. In fact, J. Michael Bailey
of Northwestern University and his co-workers estimate that the
overall heritability of sexual orientation--that proportion of the
variance in a trait that comes from genes-- is about 53 percent for
men and 52 percent for women. (The family clustering is most obvious
for relatives of the same sex, less so for male- female pairs.)
To evaluate the genetic component of sexual orientation and to clarify
its mode of inheritance, we need a systematic survey of the extended
families of gay men and lesbians. One of us (Hamer), Stella Hu,
Victoria L. Magnuson, Nan Hu and Angela M. L. Pattatucci of the
National Institutes of Health have initiated such a study. It is part
of a larger one by the National Cancer Institute to investigate risk
factors for certain cancers that are more frequent in some segments of
the gay population.
Although most of the anatomical and functional studies done so far
have focused on the cerebral cortex, which is responsible for the
higher intellectual and cognitive functions of the brain, other
researchers, such as Dr. Simon LeVay, have shown that there are gender
differences in more primitive parts of the brain, such as the
hypothalamus, where most of the basic functions of life are
controlled, including hormonal control via the pituitary gland. LeVay
discovered that the volume of a specific nucleus in the hypothalamus
(third cell group of the interstitial nuclei of the anterior
hypothalamus) is twice as large in heterosexual men than in women and
homosexual men, thus prompting a heated debate whether there is a
biological basis for homosexuality . Dr. LeVay wrote an interesting
book about the sex differences in the brain, titled "The Sexual Brain"
.
During the development of the embryo in the womb, circulating hormones
have a very important role in the sexual differentiation of the brain.
The presence of androgens in early life produces a "male" brain. In
contrast, the female brain is thought to develop via a hormonal
default mechanism, in the absence of androgen. However, recent
findings have shows that ovarian hormones also play a significant role
in sexual differentiation.
One of the most convincing evidences for the role of hormones, has
been shown by studying girls who were exposed to high levels of
testosterone because their pregnant mothers had congenital adrenal
hyperplasia . These girls seem to have better spatial awareness than
other girls and are more likely to show turbulent and aggressive
behavior as kids, very similar to boys'. But do these differences mean
a superiority/inferiority relationship between men and women?
The hormones, determine the distinct male, female or homosexual
organisation of the brain as it develops in the womb. We share the
same sexual identity for only the first few weeks after conception.
Thereafter, in the womb, the very structure and pattern of the brain
begins to take specifically male, female or homosexual form.
Throughout infant, teenage, and adult life, the way the brain was
forged will have, in subtle interplay with the hormones, a fundamental
effect on the attitudes, behavior, and intellectual and emotional
functioning of the individual. Most neuroscientists and researchers
into the mysteries of the brain are now prepared, like the American
neurologist Dr Richard Restak, to make the confident assertion "it
seems unrealistic to deny any longer the existence of male and female
brain differences. Just as there are physical dissimilarities between
male and females . . . there are equally dramatic differences in brain
functioning". The way our brains are made effects how how we think,
learn, see, feel, smell, communicate, love, make love, fight, succeed,
or fail. Understanding how our brains, and those of others, are made
is a matter of no little importance.
Infants are not blank slates, on whom we scrawl instructions for
sexually-appropriate behavior. They are born with male, female or
homosexual minds of their own. They have, quite literally, made up
their minds in the womb, safe from the legions of social engineers who
impatiently await them.