Scientific studies on homosexuality 
Autor: Caprica 7 | Publicado: 2014-09-29T21:09:00-07:00








Much has been debated about equal rights for same-sex civil marriage, but little emphasis is given to scientific bases that support that homosexuality is structurally and physiologically natural in the human brain.



HUNDREDS of scientific studies in scientific journals of high impact and high reliability &nbsp;are available in English, and support that homosexuality is not choice, it's a biological condition. There are studies done testing animals, and also in post-mortem humans (and some published studies are available on the links below) that prove that sexuality is a result of hormonal conditions even during fetal life, before birth, and that emerge at puberty.&nbsp;



Look at the figures 4 and 6 of this &nbsp;scientific article in this PDF link (http://1drv.ms/1qjQmWC)


This article shows very clearly what happens to pregnant females induced with testosterone during the fetal period in rats. The opposite is also true, high amounts of estradiol in the fetal period can feminize a male.

















Another article that supports this thesis is this mini review is http://1drv.ms/1qjUvKc, which is compiled of 76 other papers around the world, the most experienced guys in the area, and explains why, in both humans and animals, this hormonal system functions in the fetus.


Notice in Figure 2 (Theoretical model illustrating how fluctuations around an average concentration of testosterone (T) during embryonic life could lead to a heterosexual or homosexual). Low concentrations of testosterone during fetal life of a boy, would take him to be bi, gay or even transsexual (as lower the testosterone produced by him during the fetal stage - yes, boys fetuses produce MUCH testosterone during the first couple of months of life). The same thing would happen with girls fetuses had a certain blood testosterone, either the mother or fetus, could lead to homosexuality in girls, or even transsexualism.&nbsp;












An analogy could be this: Imagine as if the baby in the womb were a glass of milk, and you can put Chocolate (boy) or Strawberry (girl) ... or both. Remembering, the mother is always full of strawberry flavor.&nbsp;







Hormones can change in the body. Testosterone can be converted to progesterone and even estrogen, depending of enzymes present in the body.



GETTING DEEP IN THE SCIENCE: (bold for important conclusions)










A study published in the journal Endocrinology (Endocrinology), says that sexual orientation is a sexually differentiated trait (more than 90% of men are attracted to women and vice versa). In animals and humans, many sexual characteristics are organized during the prenatal period by sex steroids, and we can say that the same mechanism also affects human sexual orientation. The clinical conditions associated with significant endocrine changes during embryonic life often result in an increased incidence of homosexuality. The prenatal endocrine environment has a significant influence on human sexual orientation, but a large fraction of the variance in this behavioral characteristic remains unexplained to date. The genetic differences that affect behavior, either directly or by altering the secretion of embryonic hormones may also be involved. (Copyright © 2011 by The Endocrine Society doi: 10.1210 / en.2011-0277 Received March 10, 2011 Accepted May 31, 2011 Endocrinology, August 2011, 152 (8): 2937-2947 endo.endojournals.org 2937)&nbsp;



Despite that there is still no consensus as and when they are formed responsible for gender identity in most animal brain structures (hypothalamus and amygdala) (if children are born like this or it develop at puberty, or both), there is consensus that&nbsp;these structures in the brain (hypothalamus) has structural and physiological differences between heterosexual men, gay men, transgender male to female, female to male transsexual, heterosexual women and homosexual women, regarding sexual identity and sexual attraction.&nbsp;



New evidence indicates that sexual differentiation of the human brain occurs during fetal and neonatal development, and planning our gender identity and our sense of being male or female, as well as our sexual orientation as heterosexual, homosexual, or bisexual.&nbsp;The sexual differentiation process is accompanied by many structural and functional differences between these groups brain.&nbsp;



Garcia-Falgueras and Swaab said in a summary of his 2010 study,&nbsp;"The fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge. Accordingly, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation are programmed or organized into our brain structures when we are still in the womb. there is no indication that the social environment after birth has an effect on gender identity or over sexual orientation. "



In previous studies, The Savic laboratory detected a differentiation of the anterior hypothalamus in heterosexual men and heterosexual women, and an almost inverted, atypical in homosexual men and homosexual women. The hypothalamus, which is a small region of the brain located in the anterior commissure is involved in many different functions, including reproduction. These observations raised several issues, one of which was whether the described sexual dimorphism could be atypical in homosexual individuals, even with respect to factors not directly associated with reproduction.&nbsp;



In a recent article, Savic and Lindstro reported that hemispheric relations, as well as patterns of connectivity with the amygdala, are atypical in homosexual individuals, displaying patterns more similar to heterosexual women than heterosexual men, and homosexual women exhibit similar patterns more like heterosexual men than heterosexual women (1, 2).&nbsp;



The volumes of four groups of cells in this region (interstitial nuclei of the anterioror hypothalamus, or INAH 1, 2, 3 and 4, were measured in postmortem tissue from three groups of subjects: women, men who were heterosexual during their lifetime, and known to be homosexual men. No differences were found among the volumes of the cochlear nuclei of the hypothalamus INAH 1, 2 or 4&nbsp;But the sub-nucleus INHA 3 was more than twice as large in heterosexual men than in women. It was also, however, more than twice as large in heterosexual men as in homosexual.&nbsp;This finding indicates that INAH 3 is dimorphic with sexual orientation, at least in men, and suggests that sexual orientation has a biological features.&nbsp;It was first demonstrated that the volume and number of neurons in the brain in the interstitial nucleus of the anterior hypothalamus 3 (INAH3) of male to female transsexuals is similar to that of heterosexual women-control. The female-to-male transsexual had a INAH3 volume and number of neurons within the range of male control, although that treatment with testosterone that person out stopped three years before her death (3) (http://1drv.ms / 1qcY97M).&nbsp;



The results and comparisons with the control group indicate that the feminization of the interstitial nucleus of the anterior hypothalamus 3 (INAH3) from &nbsp;transgender woman was not due to estrogen treatment performed and proposes that sexual inversion.&nbsp;INAH3 in transsexual people is at least part, a marker of early sexual differentiation of the brain and that the changes in INAH3&nbsp;and can belong to a complex network that may structurally and functionally be related to gender identity (3) (http://1drv.ms/1qcY97M ).&nbsp;



I know it is complicated for those who are outside the biological sciences, neurological, etc, but take a look at the figures, especially http://1drv.ms/1qcY97M figure 8, which shows that male brains have more cells in the same region (black dots) INAH3 than female brains ... and that transgender men-to-women seem more like brains of women.&nbsp;



In the branch of the science of genetics several studies have been conducted to investigate hereditary origins of homosexuality. One of the best known studies in this direction attempts to establish a correlation between male homosexuality with the Xq28 gene. It is effectively a thesis that puts homosexuality not as a choice or lifestyle, but rather as a result of genetic variation. Consider, however, that there are studies that contradict the influence of the Xq28 gene for explaining homosexual. In a new study conducted by KAIST was possible to artificially create homosexual behavior in female rats through genetic manipulation.&nbsp;In this study, some genes related to balance the hormone estrogen have been intentionally suppressed by checking a statistically relevant homosexual preference to a control group, launching new evidence that homosexual behavior in mammals may have a genetic factor.&nbsp;




"Epigenetic 'tags' linked to homosexuality in men...&nbsp;

Twin study reveals five DNA markers that are associated with sexual orientation.




Twin studies and family trees provide strong evidence that sexual orientation is at least partly genetic. When one identical twin is gay, there is about a 20% chance that the other will be as well1. But because this rate is not 100%, it is thought that environmental factors play a role as well. One of the best characterized is the 'older brother effect': the chance of a man being gay increases by 33% for each older brother he has2. The reason is not clear, although one hypothesis holds that the mother’s immune system begins to react against male antigens and alter the fetus’s development.

To search for factors that could mediate a link between environment and genes, geneticist Eric Vilain at the University of California, Los Angeles (UCLA), and his colleagues looked at&nbsp;epigenetic markers— chemical changes to DNA that affect how genes are expressed, but not the information they contain. These 'epi-marks' can be inherited, but&nbsp;can also be altered by environmental factors&nbsp;such as smoking, and are not always shared by identical twins

The researchers collected DNA samples in saliva from 37 pairs of identical twins in which only one twin was gay, and 10 pairs in which both were gay. By scanning the twins’ epigenomes, the researchers found five epi-marks that were more common among the gay men than in their genetically identical straight brothers. An algorithm they developed based on the five epi-marks could correctly predict the sexual orientation of men in the study 67% of the time. UCLA computational geneticist Tuck Ngun will present the work on 8 October at the American Society of Human Genetics meeting in Baltimore, Maryland."



Trans Women created by Nature or God (whatever you wanna call):

Another factor that leads us to believe in the power of natural hormonal factor is: A woman who has the complete androgen insensitivity syndrome (CAIS). It is a seemingly normal woman with desires of heterosexual woman, born with all feminine attributes but is GENETICALLY MAN, and the gonads in these women are not ovaries, but instead are undescended testicles. Soon they are sterile, they can not have children, and then also do not menstruate, do not have the underarm hair, and has problems like (small) not fully developed vagina. Otherwise, women are perfect, indistinguishable to the layman, and living a lifelong heterosexual women. Holders of CAIS were never influenced by testosterone, not during fetal life, thus their bodies and brains grow up believing that they were female. The person with CAIS produces lots of testosterone, but as it is not identified by cell receptors, ie, no cell of her body realizes that there is a lot of testosterone there ... no matter how much testosterone due to one or more genetic mutations, and therefore, do not generate the masculinizing effects of the organism, not even in the brain.



It's like she does not feel the taste of chocolate, even eating dark chocolate...&nbsp;http://en.wikipedia.org/wiki/Complete_androgen_insensitivity_syndrome







Women with complete androgen insensitivity are born female, despite having a 46, XY karyotype, genetically male. http://en.wikipedia.org/wiki/Complete_androgen_insensitivity_syndrome&nbsp;



Major global health organizations, including many of psychology, no longer consider homosexuality a disease, disorder or perversion. Since 1973, homosexuality is no longer classified as such by the American Psychiatric Association. In 1975 the American Psychological Association adopted the same procedure, failing to consider homosexuality a disease. [20] In Brazil, in 1984, the Brazilian Association of Psychiatry (ABP) stood against discrimination and considered homosexuality as something not harmful to society. [21] in 1985, BPA was followed by the Federal Council of Psychology, who stopped considering homosexuality a sexual deviation and, in 1999, established rules for the work of psychologists in relation to issues of sexual orientation, stating that "homosexuality is not an illness or disorder or a perversion" and that psychologists do not collaborate with events and services that propose the treatment and / or cure of homosexuality. [22] [23] on May 17, 1990, the Assembly -General of the World Health Organization (acronym WHO) removed homosexuality from its list of mental illnesses, the International Classification of Diseases (ICD acronym). [23] [20] Finally, in 1991, Amnesty International has considered the discrimination against homosexuals a violation of human rights. The American Psychiatric Association, the American Psychological Association and the National Association of Social Workers in 2006 stated: There is currently no scientific consensus about the specific factors that lead an individual to become heterosexual, homosexual or bisexual, including possible biological, psychological and social effects of the sexual orientation of the parents. However, the available evidence indicates that the vast majority of lesbians and gay adults were raised by heterosexual parents and the vast majority of children raised by gay and lesbian parents grow up to be heterosexual. - [93]&nbsp;The Royal College of Psychiatrists in 2007 stated:&nbsp;Despite almost a century of psychoanalytic and psychological speculation, there is no substantive evidence to support the suggestion that the nature of parenting or early experiences of childhood play any role in shaping the fundamental orientation of a heterosexual or homosexual person. It seems that sexual orientation is biological in nature, determined by a complex interaction of genetic factors and the early uterine environment. Sexual orientation is therefore not a choice.&nbsp;-&nbsp;[94]&nbsp;The American Academy of Pediatrics stated in Pediatrics in 2004: Sexual orientation probably is not determined by any one factor but by a combination of genetic, hormonal and environmental influences. In recent decades, theories based on biological factors have been favored by experts. Yet there remains controversy and uncertainty as to the genesis of the diversity of human sexual orientations, there is no scientific evidence that abnormal parents, sexual abuse or any other adverse life event influencing sexual orientation. Current knowledge suggests that sexual orientation is usually established during childhood.&nbsp;





Okay, so some questions may arise, such as:&nbsp;





- Why in my day there &nbsp;was not as many gays now?&nbsp;



For cultural reasons, sexual freedom and expression has been achieved in several countries, including Brazil, this leads to greater acceptance of homosexuality as part of people's lives, and increasingly, early teens want to be accepted by what they really feel, then there is a pressure that homosexuality to be no longer a taboo, as this taboo is broken as more homosexuals assume.



- I'm straight and I had homossexual sex once and hadn't enjoyed, I'm gay?&nbsp;



Homosexual behavior is well understood in animals and in man, in what situations where there are no females present, many males have homosexual behaviors, is the case of prisons, for example, or when for some reason in nature, there are no females available for mating .&nbsp;



Sexual behavior can indeed be an isolated case of sexuality. A person may have made a choice to try and not like it, because it never felt attracted. Humans can rationally choose to suppress their instinctual desires and make choices often against their innermost desires.&nbsp;



- I know a guy who has been married for life, had children and became gay. What happened?&nbsp;



Well, humans are too complex to put everything in a few lines. It may be that your friend has always been bisexual, and chose one over the other. OR may also be that he was always gay, but then chose to live with the opposite sex, repressing homosexual desires and living a different life. Then he chose to respect his instincts.



Furthermore, it may be that his brain has changed due to some factor. For example, there is the case of Phineas Gage. Phineas Gage (1823-1860) was an American worker who, in an accident with explosives, had his brain crossed by a metal bar, surviving despite the severity of the accident. Gage's case is regarded as one of the first scientific evidence that the injury to the frontal lobes can change the personality, emotions and social interaction. http://pt.wikipedia.org/wiki/Phineas_Gage&nbsp;





REFERENCES&nbsp;



http://1drv.ms/1qcY97M&nbsp;



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http://1drv.ms/1qjObSW&nbsp;



http://1drv.ms/1qjONbt&nbsp;



http://1drv.ms/1qjPS2O&nbsp;



http://1drv.ms/1qjQ7Lh&nbsp;



http://1drv.ms/1qcXUtu&nbsp;



(1) Dick F. Swaab. (July 2008). "Sexual orientation and its basis in brain structure and function" 105 (30): 10273-10274. PNAS - Proceedings of the National Academy of Sciences of the United States of America.&nbsp;



(2) Ivanka Savic and Per Lindström. (July 2008). "SPET and MRI show differences in cerebral asymmetry and functional connectivity between homo-and heterosexual subjects" 105 (27): 9403-9408. PNAS - Proceedings of the National Academy of Sciences of the United States of America.&nbsp;



(3) Alicia Garcia-Dick F. Swaab and Falgueras. (Nov 2008). "The difference in the hypothalamic fri&nbsp;

uncinate nucleus: relationship to gender identity "131 (12): 3132-3146 Brain - A journal of neurobiology..