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Gay Gene
The relationship between biology and sexual orientation is a subject of ongoing research. While scientists do not know the exact cause of sexual orientation, they theorize that it is caused by a complex interplay of genetic, hormonal, and environmental influences. However, evidence is weak for hypotheses that the postnatal social environment impacts sexual orientation, especially for males. Biological theories for explaining the causes of sexual orientation are favored by scientists. These factors, which may be related to the development of a sexual orientation, include genes, the early uterine environment (such as prenatal hormones), and brain structure. While the evolutionary explanation for heterosexuality in organisms that reproduce sexually is straightforwardly understood to be a psychological adaptation resulting from greater reproductive success, evolutionary explanations for homosexuality rely upon other mechanisms of evolution such as kin selection and inclusive fitn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Orientation
Sexual orientation is an enduring personal pattern of romantic attraction or sexual attraction (or a combination of these) to persons of the opposite sex or gender, the same sex or gender, or to both sexes or more than one gender. Patterns are generally categorized under heterosexuality, homosexuality, and bisexuality, while asexuality (experiencing no sexual attraction to others) is sometimes identified as the fourth category. These categories are aspects of the more nuanced nature of sexual identity and terminology. For example, people may use other labels, such as '' pansexual'' or '' polysexual'', or none at all. According to the American Psychological Association, sexual orientation "also refers to a person's sense of identity based on those attractions, related behaviors, and membership in a community of others who share those attractions". ''Androphilia'' and ''gynephilia'' are terms used in behavioral science to describe sexual orientation as an alternative to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterozygote Advantage
A heterozygote advantage describes the case in which the heterozygous genotype has a higher relative fitness (biology), fitness than either the homozygous Dominance (genetics), dominant or homozygous recessive gene, recessive genotype. Loci exhibiting heterozygote advantage are a small minority of loci. The specific case of heterozygote advantage due to a single locus (genetics), locus is known as overdominance. Overdominance is a rare condition in genetics where the phenotype of the heterozygote lies outside of the phenotypical range of both homozygote parents, and heterozygous individuals have a higher fitness (biology), fitness than homozygous individuals. Polymorphism (biology), Polymorphism can be maintained by Natural selection, selection favoring the heterozygote, and this mechanism is used to explain the occurrence of some kinds of genetic variation, genetic variability. A common example is the case where the heterozygote conveys both advantages and disadvantages, while bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intersex
Intersex people are those born with any of several sex characteristics, including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical binary notions of male or female bodies". Sex assignment at birth usually aligns with a child's external genitalia. The number of births with ambiguous genitals is in the range of 1:4,500–1:2,000 (0.02%–0.05%). Other conditions involve the development of atypical chromosomes, gonads, or hormones. The portion of the population that is intersex has been reported differently depending on which definition of intersex is used and which conditions are included. Estimates range from 0.018% (one in 5,500 births) to 1.7%. The difference centers on whether conditions in which chromosomal sex matches a phenotypic sex which is clearly identifiable as male or female, such as late onset congenital adrenal hyperplasia (1.5 percentage points) and Kline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ivanka Savic
Ivanka Savic Berglund (born 1953) is a Serbian-Swedish neuroscientist, a professor of neurology and chief physician at the Karolinska Institute in Sweden, and an adjunct professor in the neurology department at the University of California, Los Angeles (UCLA). * Savic is best known for her neurophysiology and neuroimaging research relating to epilepsy, sex differences, sexual orientation, gender identity, brain processing of odors and pheromones, and the effects of chronic stress on the brain. Savic is a co-founder of the Stockholm Brain Institute and the editor of several medical books. Education and career Savic was born in Belgrade, Serbia in 1953 to a family of high ranking military officers and academics. She began her medical studies at Uppsala University in Sweden, graduated as a doctor at Karolinska Institute (KI) in 1978 and became a certified doctor in 1980. In 1984 she became a specialist in neurology and in 1991 in clinical neurophysiology. Savic received her PhD ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homosexual Behavior In Sheep
Homosexual behavior in sheep has been well documented and studied. The domestic sheep (''Ovis aries'') is the only species of mammal except for humans which exhibits exclusive homosexual behavior. "About 10% of rams (males) refuse to mate with ewes (females) but do readily mate with other rams." Thirty percent of all rams demonstrate at least some homosexual behavior. One report on sheep found that 8% of rams exhibited homosexual preferences—that is, even when given a choice, they chose male over female partners. This documented homosexual preference has garnered much discussion. Such rams prefer to court and mount other rams only, even in the presence of estrous ewes. Moreover, around 18–22% of rams are bisexual. Several observations indicate that male–male sexual preference in rams is sexually motivated. Rams routinely perform the same courtship behaviors (including foreleg kicks, nudges, vocalizations, anogenital sniffs and flehmen) prior to mounting other males as obs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simon LeVay
Simon LeVay (born 28 August 1943 in Oxford, England) is a British-American neuroscientist. He received a bachelor's degree in natural sciences from the University of Cambridge in 1966, a Ph.D. in Neuroanatomy at the University of Göttingen in Germany, and completed his postdoctoral fellowship at Harvard Medical School in 1974. LeVay held positions in neurobiology at the Harvard Medical School from 1974 to 1984. He then worked at the Salk Institute for Biological Studies from 1984 to 1993 while holding an Associate Professorship in Biology at the University of California, San Diego. Much of his early work focused on the visual cortex in animals. While working at the Salk Institute for Biological Studies, LeVay published an article in ''Science'' that compared the size of the " Interstitial Nucleus of the Anterior Hypothalamus" ( INAH3) in a group of gay men to a group of straight men and women. This was the first scientific study ever published that showed brain differences ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
INAH 3
INAH-3 is the short form for the third interstitial nucleus of the anterior hypothalamus, and is the sexually dimorphic nucleus of humans. The INAH-3 is significantly larger in males than in females regardless of age and larger in heterosexual males than in homosexual males and heterosexual females. Homologs of the INAH-3 have been found to play a direct role in sexual behavior in quails, rhesus macaques, sheep, rats, mice, and ferrets. Research The term INAH (interstitial nuclei of the anterior hypothalamus), first proposed in 1989 by a group of the University of California at Los Angeles, refers to 4 previously undescribed cell groups of the preoptic-anterior hypothalamic area (PO-AHA) of the human brain, which is a structure that influences gonadotropin secretion, maternal behavior, and sexual behavior in several mammalian species. There are four nuclei in the PO-AHA (INAH1-4). One of these nuclei, INAH-3, was found to be 2.8 times larger in the male brain than in the fema ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraternal Birth Order Effect
Fraternal birth order, also known as the older brother effect, has been correlated with male sexual orientation, with a significant volume of research finding that the more older brothers a male has from the same mother, the greater the probability he will have a homosexual orientation. Ray Blanchard and Anthony Bogaert first identified the association in the 1990s and named it the fraternal birth order effect. Scientists have attributed the effect to a Prenatal development, prenatal biological mechanism, since the association is only present in men with older biological brothers, and not present among men with older step-brothers and adoptive brothers. The mechanism is thought to be a maternal immune response to male fetuses, whereby antibodies neutralize male Y-proteins thought to play a role in sexual differentiation during development. This would leave some regions of the brain associated with sexual orientation in the 'female typical' arrangement – or attracted to men. The e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gay Men
Gay men are male homosexuals. Some bisexual men, bisexual and homoromantic men may dually identify as ''gay'' and a number of gay men also identify as ''queer''. Historic terminology for gay men has included ''Sexual inversion (sexology), inverts'' and ''Uranian (sexology), uranians''. Gay men continue to face significant Discrimination against gay men, discrimination in LGBT rights by country or territory, large parts of the world, particularly in most of LGBT rights in Asia, Asia and LGBT rights in Africa, Africa. In the LGBT rights in the United States, United States and the western world, many gay men still experience discrimination in their daily lives, though some openly gay men have reached national success and prominence, including Apple Inc., Apple CEO Tim Cook and heads of state or government such as Edgars Rinkēvičs (president of Latvia since 2023). The word ''gay'' is recommended by LGBTQ groups and style guides to describe all people exclusively attracted to m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
