Is Sexual Orientation Genetic Sociology Essay

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1st Jan 1970 Sociology Reference this

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In this modernised world sex and relationship plays an important role as sexuality is part of who we are as humans. Sexuality defines how we see ourselves and how we physically relate to others beyond having the ability to reproduce. Sexuality is made up of three components which include biological sex, gender identity, and social gender role. In a less brief context, biological sex is the anatomical, physiological, and genetic characteristics associated with being a male or female, gender identity means the physiological sense of being a male or female and social gender role is the cultural norms that define feminine and masculine behaviour (1).

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Sexual orientation is known as an enduring pattern of emotional, romantic and sexual attractions to men, women or both sexes besides also referring to a person’s sense of identity based on those attractions, related behaviours and memberships in a community of others who share those attractions which may or may not be evident in a person’s appearance or behaviour. People may choose not to act on such feelings as having attractions to people of the same sex or opposite sex. For example, a bisexual who can be attracted to members of either sex may choose to have a one partner relationship with one gender, therefore, choosing not to act on the attraction of another gender (1).

Three commonly recognized aspect of sexual orientation are heterosexuality, bisexuality, homosexuality and one uncommon aspect is asexuality which is when a person has no sexual attraction or interest in sexual activity. Therefore, sexual orientation differs from sexual behaviour in that it involves an individual’s feelings and perception of their own sexuality. According to current scientific and professional understanding, the core attractions that form the basis for adult sexual orientation typically emerge between middle childhood and early adolescence. These patterns of emotional, romantic, and sexual attraction may arise without any prior sexual experience.

Heterosexuality is the attraction to individuals of the other gender which is

the cultural normality for the behaviour of males and females. For example, males and females being attracted to individuals of the opposite sex.

Bisexuality is the attraction to members of either gender, as an example a male having a sexual relationship with another male partner as well with a female partner.

On the other hand, homosexuality can be defined as the attraction to members of the same gender, are not completely understood by scientists.

Scientists have pondered the theory for many years that sexual preference is a learned behaviour that is developed during early childhood. There are many theories regarding how a particular sexual orientation develops. Some scientists share the view that sexual orientation is shaped at an early age through interactions of biological, psychological and social factors. Other psychologists, psychiatrists and mental health professionals agree that

homosexuality may be genetically predetermined.

Research over the past thirty-five years has determined that homosexuality is not an illness, mental disorder or emotional problem. Other objective research shows that homosexual

orientation is not associated with emotional or social problems. Because sexual orientation develops in early adolescence, without any prior sexual experience, it is believed that it is not chosen. It has been reported that some people try diligently to change their sexual preference from homosexual to heterosexual with no success. For this reason, psychologists do not consider sexual orientation to be a conscious choice that can be voluntarily changed.

An untrue stereotype about homosexuals is the belief that gay men have more of a tendency

than heterosexual men to sexually molest children. There is no evidence of this. Instead, recent studies have shown that homosexual parents are quite capable of rearing developmentally secure children who are intelligent, as well as being psychologically well adjusted. There is no evidence that homosexual parents are less capable of parenting than heterosexual parents. Because therapy cannot change sexual orientation, it is important for society to become better educated about homosexuality, thus diminishing anti-gay prejudice.

Accurate information for young people struggling with their own sexual identity is especially

important. The belief that such information when given to young people will affect one’s sexual orientation is not valid. The people who have the most positive attitudes toward gay men and lesbians are those who say they know one or more gay persons well. For this reason, psychiatrists believe that discrimination against homosexuality is based on his or her lack of knowledge concerning gay people. Therefore, educating all people about sexual orientation

and homosexuality is likely to diminish anti-gay prejudice.

Homosexuality was once believed to be a mental illness, due to the unfortunate

fact that mental health professionals furnished society with incorrect information. Most studies about homosexuals only involved gay men and lesbians who were in therapy. They were seeking help for their problems, just as straight men and women do. These studies, and the misunderstanding of homosexuality, seriously damaged the acceptance of gay men and lesbians. The theories of homosexuals by psychologists, psychiatrists and other mental health

professionals, painted an untrue portrait of gay men and lesbians. This unfair portrayal directly attributed to the un-acceptance of homosexuals.

In 1973, the American Psychiatric Association confirmed that homosexuals were not mentally ill, and it was not until two years later in 1975, that the American Psychological Association passed a resolution supporting this confirmation. Both associations urged all mental health professionals to help dispel the stigma of mental illness that had been associated with homosexual orientation. Since this original declassification of homosexuality as a mental disorder, this decision has been reaffirmed by additional research findings and by both associations.

However, when one is reared to believe a certain way, it is not easy to change his or her opinion. Psychiatrists, psychologists and the Lord above could urge one to rethink a learned fact; however, to dispute a theory learned early in life is sometimes impossible. This unfair discrimination against homosexuals is an obstacle to their leading a normal, happy and productive life, which is the desire of gay men and lesbians, just as it is the desire of straight men and women. Research has shown a high rate of violence, as well as discrimination, against homosexuals. Just as it is with straight men, the more positive the gay male identity, the better one’s mental health will become and the higher one’s self-esteem will be. To accomplish this, the acceptance of gay men and lesbians as productive citizens, without prejudice, is necessary. Protection against violence and discrimination would not be necessary if one understood that gay men and lesbians are just like you and me; the only difference is their sexual preference.

Most scientists today agree that sexual orientation is the result of a combination of environmental, hormonal, and genetic factors. In other words, there are many factors that contribute to a person’s sexual orientation, and the factors may be different for different people.

In other words, we intend to research in depth on each factor stated and how does it affect a person’s sexual orientation then come to a conclusion if sexual orientation is genetic relating back to our topic. This is the prime objective of this project. To arrive at our objectives, we have to research about the other factors affecting sexual orientation.

Therefore, we have divided each factor into 3 subsequent chapters. Chapter 2 will be a detailed explanation on how genetic factors contribute to sexual orientation. Chapter 3 consequently will be discussing on environmental and emotional factors in relation to sexual orientation. Besides that, Chapter 4 is on the role played by hormones in determining a person’s sexual orientation. All these 3 chapters will be discussing sexual orientation on homosexuality and bisexuality.

The final chapter will relate back to our main topic which is ‘Is Sexual Orientation Genetic?’ A conclusion will be brought about based on the research, studies and evidences done on the previous 3 chapters.

Chapter 2 : Genetic Factors

Chromosomes in humans can be divided into two types which is autosomes and sex chromosomes. The sex chromosomes contain certain genetic traits link to a person’s sex. It can be XX with phenotype female and XY with phenotype male. On the other hand, the autosomes contain the rest of the genetic hereditary information. Both autosomes and sex chromosomes act in the same way during cell division. There are 23 pairs of chromosomes of which 22 pairs of autosomes and 1 pair of sex chromosome giving a total of 46 per cell for one human. A person’s sex is determined by the sex chromosome (wiki chromosome).

Based on a research conducted by scientists on November 8th 2007, new evidences have been uncovered showing genetics has a role to play in determining whether an individual is homosexual or heterosexual. Dr. Sandra Witelson, a neuroscientist in the Michael G. DeGroote School of Medicine at McMaster University, and colleges at Sunnybrook Health Sciences Centre in Toronto conducted the research on studies of the brains of healthy, right handed, 18 to 35- year old homosexual and heterosexual men using magnetic resonance imagining (MRI). About 10 years ago, which is now accepted as fact, studies have demonstrated that there is a higher proportion of left-handers in the homosexual population than the general population. Consequently, in other research it was found that left-handers have a larger region of the posterior corpus callosum which is the thick band of nerve fibres connecting the two hemispheres of the brain compared to the right- handers. Furthermore, the posterior part of the corpus callosum is larger in homosexual than heterosexual men. The size of corpus callosum is largely inherited suggesting a genetic factor in sexual orientation. A correlational analysis by researchers which included size of the corpus callosum, and test scores on language, visual spatial and finger dexterity tests. Prediction on sexual orientation in 95 per cent of the cases was done by using all these variables.

A report by the National Cancer Institute researchers states that the appearance that many homosexual men inherit a gene from their mothers that influences sexual orientation. It was suggested that inherited genetic factors at least play a role in determining sexual orientation. The study’s lead author Dean Hamer, chief of the cancer institute’s section on Gene Structure and regulation concluded that it is basically not a choice or a decision to be a gay. However, people have no control over the genes inherited and there is no way to change it. The family histories of 114 gay men were studied and it was found that more homosexual brothers, uncles and male cousins than would be expected in the general population whereby some families had three generations of homosexual relatives. It was suggested that something inherited was going on since the uncles and cousins were not raised in the same household but do share genetic information.

Following up another studies was made on the DNA from 40 pairs of homosexual brothers and it was found that 33 of them shared same genetic markers on the X chromosome in a region known as Xq28. The X chromosomes are always inherited from mothers. Genes consist of tiny coils of DNA, deoxyribonucleic acid, which carries the instructions to manufacture a particular body substance. No such similar sharing was present in the same region among heterosexual men. It is expected that this region will be important for both heterosexual and homosexual development providing very small and subtle difference between the genes of each group. However, the finding does not explain all homosexuality. Seven out of 40 pairs of homosexual brothers studied did not have the common genetic factor.

Part of the studies state that the cancer Kaposi’s sarcoma unusually afflicts large numbers of homosexuals. Further study is being conducted to determine whether a similar genetic link occurs in families of homosexual women hoping to identify the specific gene involved in sexual orientation.

Gregory King, spokesman for the Human Rights Campaign Fund, a gay and lesbian activist group, said he hoped from the studies it would help Americans understand that most lesbian and gay people do not choose their sexual orientation. Despite, concerns are there among people who are lesbians and gay that this discovery will be misused to suggest that homosexuality is something that needs to be corrected.

According to the variation in sexual orientation, heritability studies have differed on the precise contribution of genetics, though a few linkage studies have indicated a possible role for certain genes on the X chromosome. However, the strength of that evidence is limited due to the conflicting nature of the reports and small sample sizes. Some of the questions in relation to the possible genetic underpinnings of sexual orientation have been clarified by a more recent study conducted by the first ever genome-wide association study (GWAS) on sexual orientation. It is also in relation to the release of a web-based survey to the large 23andMe database of over 180,000 individuals.

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Furthermore, the other non-genetic phenotypes associated with sexual orientation are also explored. The objective is to understand the relationship between sexual orientation and non-genetic phenotypes as the data collected was extracted from dozens of 23andMe surveys taking into consideration thousands of conditions and trait. Research has shown that lesbians are more likely than heterosexual women to have alcoholism and alcohol-related problems (3). A number of studies have also found that women with same sex partners are more likely to have psychiatric disorders, including major depression (4) and men with same sex partners are more likely to have anxiety and mood disorders (5).

Phenotype analyses were conducted using linear or logistic regression. In statistics, linear regression is the relationship between a scalar dependent variable Y and one or more explanatory variables denoted X as the data modelled using linear predictor functions, and unknown model parameters are estimated from the data. Logistic regression is a type of analysis used to predict the outcome of a categorical dependent variable based on one or more predictor variables that is used in estimating empirical values of the parameters in a qualitative response model(wiki). The reported betas are the change on the sexual identity scale per unit of the other phenotype. Both the phenotype analyses and GWAS analyses controlled for age, the first five principal components, and attitudes towards homosexuality as collected in the Sexual Orientation Survey. GWAS analyses were conducted in individuals of European descent.

The questions asked for this study to over 23,000 individuals 23andMe database is as follows:

The survey counts based on the questions asked were as below:

They have examined the correlation between sexual identity and ~1000 phenotypes already characterized in the 23andMe database through other surveys. These analyses were preliminary as outliers or confounders beyond what is listed in the methods were not checked. Previous ¬ndings were replicated showing a positive association between lesbians and alcoholism, and between lesbians and gay men and several psychiatric conditions.

Chapter 3 : Environmental and Emotional Factors

On the development of human sexual orientation, another possible factor is the environmental and emotional influences. Many influences or factors lead to sexual orientation but no findings have emerged that permit scientists to conclude that sexual orientation is determined by any particular factor or factors. Therefore, a great deal of people thinks nature and nurture both play complex roles (wiki environment sexual orientation).

Environmental factors are associated with family influences. Evidence have been provided by researches that gay men report having had less loving and more rejecting fathers, and closer relationships with their mothers, than non-gay men. Some researchers think this may indicate that childhood family experiences are important determinants to homosexuality, or that parents behave this way in response to gender-variant traits in a child. Both possibilities might be true in different cases (wiki).

Childhood factors do affect marital choices as children who experience parental divorce are less likely to marry heterosexually than those growing up in intact families. In a broad point of view, heterosexual marriage was significantly linked to having young parents, small age differences between parents, stable parental relationships, large sibships (a group of offspring having the same two parents) , and late birth order. For men, homosexual marriage was associated with having older mothers, divorced parents, absent fathers, and being the youngest child. On the other hand, for women, maternal death during adolescence and being the only or youngest child or the only girl in the family increased the likelihood of homosexual marriage. Childhood family experiences are important determinants of heterosexual and homosexual marriage decisions in adulthood (http://link.springer.com/article/10.1007%2Fs10508-006-9062-2).

Consequently, parental sexual orientation may affect child development. Studies were focused on an early research on children with lesbian and gay parents in which the children had been born in the context of a heterosexual marriage. The developments among children of divorced lesbian mothers were compared with children of divorced heterosexual mothers and few significant differences were found. Children in the research who had been born into homes with married mothers and fathers have no obvious reasons to understand on their healthy development as the children faced early exposure to apparently heterosexual male and female role models which mainly contributes to the healthy development.

In comparison, a study conducted by Charlotte J. Patterson from University of Virginia on lesbian or gay parents who rear infants and children from offspring and it is important that the children had never lived with heterosexual parents. The study was on a group of 4 to 9 year old children who had been born to or adopted early in life by lesbian mothers. Results from in-home interviews and also from questionnaires showed that children had regular contact with a wide range of adults of both genders, both within and outside of their families. The children’s self-concepts and preferences for same-gender playmates and activities were much like those of other children their ages. Moreover, standardized measures of social competence and of behaviour problems, such as those from the Child Behaviour Checklist (CBCL), showed that they scored within the range of normal variation for a representative sample of same-aged American children. Therefore, it was clear from this study and others like it that it was quite possible for lesbian mothers to rear healthy children.

Consistent with earlier findings, results from the study revealed few differences in adjustment between adolescents living with same-sex parents and those living with opposite-sex parents . There were no significant differences between teenagers living with same-sex parents and those living with other-sex parents on self-reported assessments of psychological well-being, such as self-esteem and anxiety, measures of school outcomes, such as grade point averages and trouble in school, or measures of family relationships, such as parental warmth and care from adults and peers. Adolescents in the two groups were equally likely to say that they had been involved in a romantic relationship in the last 18 months, and they were equally likely to report having engaged in sexual intercourse. The only statistically reliable difference between the two groups is that those with same-sex parents felt a greater sense of connection to people at school compared to the youngsters living with same-sex couples. There were no significant differences in self-reported substance use, delinquency, or peer victimization between those reared by same or other-sex couples.

Although the gender of parents’ partners was not an important predictor of adolescent well-being, other aspects of family relationships were significantly associated with teenagers’ adjustment. Consistent with other findings about adolescent development, the qualities of family relationships rather than the gender of parents’ partners were consistently related to adolescent outcomes. Parents who reported having close relationships with their offspring had adolescents who reported more favourable adjustment.

The fact that children of lesbian mothers generally develop in healthy ways should not be taken to suggest that no challenges were encountered. Many investigators have remarked upon the fact that children of lesbian and gay parents may encounter anti-gay sentiments in their daily lives. For example, in a study of 10- year-old children born to lesbian mothers, Gartrell, Deck, Rodas, Peyser, and Banks (2005) reported that a substantial minority had encountered anti-gay sentiments among their peers. Those who had such encounters were likely to report having felt angry, upset, or sad about these experiences. Children of lesbian and gay parents may be exposed to prejudice against their parents in some settings, and this may be painful for them, but evidence for the idea that such encounters affect children’s overall adjustment is lacking.

Another study, published in the October 2006 issue of Archives of Sexual Behaviour, authored by Danish epidemiologist Morten Frisch and statistician Anders Hviid, reports the analysis of data from over two million men and women. It is the first study to examine an entire group of homosexuals for environmental factors in their decisions to marry homosexually. The research suggests a link between environmental factors such as geographic birthplace and family relationships and the probability of marrying a same-sex or opposite-sex partner. The massive study also finds that the number of brothers and sisters increases the probability of marrying heterosexually. This finding questions a recent, widely touted Canadian study of birth order that found the number of older brothers increased the probably of homosexuality in men.

The researchers found for each additional year one’s parents stay married, the probability of heterosexual marriage in the children increased by 1.6% among sons and 1.0% among daughters. In contrast, the rate of homosexual unions decreased by 1.8% among sons and 1.4% among daughters for every year of intact parental marriage. Summing these effects over years of childhood and adolescence contributes to a noteworthy impact.

Regarding homosexual marriages, researchers have also found that birth place relates to the sexual orientation of marriage partner. Being born in urban settings increased the probability of homosexual marriage and decreased the probability of heterosexual marriage. This study was said to be the first to show that birth place or some correlate thereof influences marital choices in adulthood.

The researchers also confirmed previous research suggesting that children who experience parental divorce are less likely to marry heterosexually than children reared in intact families. For men, unknown paternal identity, parental divorce, short duration of cohabitation with both parents, and long duration of father-absent cohabitation with mother were all associated with increased rates of homosexual marriage. For women, homosexual marriage rates were elevated among women whose parents were married briefly, and those who experienced long periods of mother absence due either to abandonment or death during the teen years.

Taken together, the study’s findings suggest that intact parents bearing multiple children and living in rural areas increase the probability of heterosexual pairings in their children. The study was not designed to examine all possible contributions to sexual orientation nor does it account for individual situations. We know, for instance, that gays and straights come from all kinds of families and locations. However, the study raises the possibility that family and social factors function to help shape adult sexual orientation.

Chapter 4: Hormonal Factors

Hormones are your body’s chemical messengers. It is released by one or more cells which travel through the bloodstream that affects cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In relation to sexuality following up the hormonal theory, exposure to certain hormones plays an act in fetal sex differentiation. Besides that, this exposure also influences the sexual orientation that emerges later in the adult.

Hormones which interact with the developing brain cells coming from the differences in brain structure are accredit to be the basis of sex differences in countless behaviour, including sexual orientation. The interaction of these hormones on the developing brain is affected by prenatal factors that can influence later the sex-typed behaviour in children.

Factors hypothesized in contributing to sex-typed behaviour concerns the same as those hypothesized to contribute to sexual orientation. Higher rates of sex-atypical behaviour in childhood and adulthood are seen in homosexual men and women compared to the same sex heterosexuals. Early hormones have been suggested to influence both sexual orientation and related childhood sex-typed behaviours. Recent studies, however, have provided evidence in support of prenatal androgen exposure influencing childhood sex-typed behaviour.

An example of the study is Early Hormonal Influences on Childhood Sex-Typed Activity and Playmate Preferences: Implications for the Development of Sexual Orientation. The hormonal influences on activity and playmate preferences in children with congenital adrenal hyperplasia (CAH) are examined. The children were in the range of ages between 2.5 to 12 years. It is observed that CAH girls preferred boys’ toys and activities and had greater preference for boy playmates than controls. On the other hand, CAH boys did not differ significantly from controls and activity and playmate preferences were not related. From this it was concluded that early androgen has a major effect on childhood activity preferences but only a weak influence on playmate preferences. Besides that, sex segregation does not arise from sex-typed activity preferences, activity and playmate preferences may be differently predictive of sexual orientation and hormonal influences on sexual orientation are likely to be complex.

Consequently, prospective and retrospective studies of childhood gender role behaviour reveal homosexual males to be more likely than heterosexual males in the sense of participating in girls’ games, to experiment with cosmetics and jewellery and to be less likely than heterosexual males to participate in sports. In the same way, lesbians analytical report shows that they were more likely than heterosexual females in the manner of participating in sports, to be called a tomboy and to be less likely than heterosexual females as in experimenting with or using cosmetics and jewellery or even to wear dresses. From reports by Bailey & Zucker, it was also known that homosexual men and women played with opposite sex playmates in childhood more that did heterosexual men and women.

However, the differences between homosexual and heterosexual individuals may not be confined to childhood activities. For example, in another report by McCormick & Witelson, it is stated that heterosexual men have higher spatial ability and lower verbal ability compared to both homosexual men and heterosexual women. Besides that, a higher rate of left-handedness has been noticed in both homosexual men and women than heterosexual comparisons.

Nonetheless, it is important to note that there are a few other sex-typed behaviours not related to sexual orientation. This is identified as most homosexual men and women have typical gender identity and are similar to same sex heterosexual individuals on aspects of mating psychology related to sexual selection that show sex differences, for example, interest in uncommitted sex. These comparisons are useful because sexual orientation differences that parallel sex differences suggest that some of the factors that cause sex differences also cause differences between homosexual and heterosexual individuals of the same sex. This is because some homosexual individuals are as sex-typical as most heterosexuals, there may be more than one cause of sexual orientation. On the other hand, when sexual orientation differences do not parallel sex differences, different etiologies are likely.

Gonadal hormones have been hypothesized to play a main role in the development of sex-typed behaviour and sexual orientation. Thus, high levels of androgen during sensitive periods of development have been suggested to produce masculine-typical behaviour, including childhood activities, cognitive abilities, and sexual orientation directed to women, that is, male heterosexuality and female homosexuality, whereas very low levels of androgen during those periods are hypothesized to result in female typical childhood activities, cognitive abilities, and sexual orientation directed to men, that is, male homosexuality and female heterosexuality.

Human sex-typed behaviour is also affected by early exposure to hormones. Thus, female participants with congenital adrenal hyperplasia (CAH), who have high levels of androgen during the prenatal and early postnatal periods, have greater preference for traditionally masculine toys and activities, higher spatial ability, and greater rates of homosexual or bisexual fantasies than controls. Similarly, female participants exposed to high levels of masculinizing or defeminizing hormones as a result of maternal ingestion during pregnancy have been reported to be more aggressive and to have higher rates of homosexual or bisexual fantasies than controls. These increases in male typical behaviour which occur in the presence of female gender identity in both CAH girls and women and those with exogenous hormone exposure.

Unusual hormone exposure in boys and men has complex relationships to behaviour. In relation, low androgen seems to result in reduced male typical behaviour. Male adolescents and adults with deficient androgen beginning early in life have shown reduced spatial ability compared with controls. High levels of masculinizing hormones have been associated with increased, decreased, and unchanged masculine typical behaviour. Male participants exposed to androgenizing progestin have been reported to be more aggressive than their brothers, but male participants with CAH and thus high levels of androgen generally show male typical behaviour. There are few systematic studies of sexual behaviour in men with unusual early hormone exposure, but homosexuality may be more common in men who are assumed to have low prenatal testosterone, for example, XXY men.

There is evidence especially in female individuals that early hormone exposure affects both sexual orientation and some of the behaviors that are related to it, providing indirect support for the hypothesis that sexual orientation typically is influenced b

In this modernised world sex and relationship plays an important role as sexuality is part of who we are as humans. Sexuality defines how we see ourselves and how we physically relate to others beyond having the ability to reproduce. Sexuality is made up of three components which include biological sex, gender identity, and social gender role. In a less brief context, biological sex is the anatomical, physiological, and genetic characteristics associated with being a male or female, gender identity means the physiological sense of being a male or female and social gender role is the cultural norms that define feminine and masculine behaviour (1).

Sexual orientation is known as an enduring pattern of emotional, romantic and sexual attractions to men, women or both sexes besides also referring to a person’s sense of identity based on those attractions, related behaviours and memberships in a community of others who share those attractions which may or may not be evident in a person’s appearance or behaviour. People may choose not to act on such feelings as having attractions to people of the same sex or opposite sex. For example, a bisexual who can be attracted to members of either sex may choose to have a one partner relationship with one gender, therefore, choosing not to act on the attraction of another gender (1).

Three commonly recognized aspect of sexual orientation are heterosexuality, bisexuality, homosexuality and one uncommon aspect is asexuality which is when a person has no sexual attraction or interest in sexual activity. Therefore, sexual orientation differs from sexual behaviour in that it involves an individual’s feelings and perception of their own sexuality. According to current scientific and professional understanding, the core attractions that form the basis for adult sexual orientation typically emerge between middle childhood and early adolescence. These patterns of emotional, romantic, and sexual attraction may arise without any prior sexual experience.

Heterosexuality is the attraction to individuals of the other gender which is

the cultural normality for the behaviour of males and females. For example, males and females being attracted to individuals of the opposite sex.

Bisexuality is the attraction to members of either gender, as an example a male having a sexual relationship with another male partner as well with a female partner.

On the other hand, homosexuality can be defined as the attraction to members of the same gender, are not completely understood by scientists.

Scientists have pondered the theory for many years that sexual preference is a learned behaviour that is developed during early childhood. There are many theories regarding how a particular sexual orientation develops. Some scientists share the view that sexual orientation is shaped at an early age through interactions of biological, psychological and social factors. Other psychologists, psychiatrists and mental health professionals agree that

homosexuality may be genetically predetermined.

Research over the past thirty-five years has determined that homosexuality is not an illness, mental disorder or emotional problem. Other objective research shows that homosexual

orientation is not associated with emotional or social problems. Because sexual orientation develops in early adolescence, without any prior sexual experience, it is believed that it is not chosen. It has been reported that some people try diligently to change their sexual preference from homosexual to heterosexual with no success. For this reason, psychologists do not consider sexual orientation to be a conscious choice that can be voluntarily changed.

An untrue stereotype about homosexuals is the belief that gay men have more of a tendency

than heterosexual men to sexually molest children. There is no evidence of this. Instead, recent studies have shown that homosexual parents are quite capable of rearing developmentally secure children who are intelligent, as well as being psychologically well adjusted. There is no evidence that homosexual parents are less capable of parenting than heterosexual parents. Because therapy cannot change sexual orientation, it is important for society to become better educated about homosexuality, thus diminishing anti-gay prejudice.

Accurate information for young people struggling with their own sexual identity is especially

important. The belief that such information when given to young people will affect one’s sexual orientation is not valid. The people who have the most positive attitudes toward gay men and lesbians are those who say they know one or more gay persons well. For this reason, psychiatrists believe that discrimination against homosexuality is based on his or her lack of knowledge concerning gay people. Therefore, educating all people about sexual orientation

and homosexuality is likely to diminish anti-gay prejudice.

Homosexuality was once believed to be a mental illness, due to the unfortunate

fact that mental health professionals furnished society with incorrect information. Most studies about homosexuals only involved gay men and lesbians who were in therapy. They were seeking help for their problems, just as straight men and women do. These studies, and the misunderstanding of homosexuality, seriously damaged the acceptance of gay men and lesbians. The theories of homosexuals by psychologists, psychiatrists and other mental health

professionals, painted an untrue portrait of gay men and lesbians. This unfair portrayal directly attributed to the un-acceptance of homosexuals.

In 1973, the American Psychiatric Association confirmed that homosexuals were not mentally ill, and it was not until two years later in 1975, that the American Psychological Association passed a resolution supporting this confirmation. Both associations urged all mental health professionals to help dispel the stigma of mental illness that had been associated with homosexual orientation. Since this original declassification of homosexuality as a mental disorder, this decision has been reaffirmed by additional research findings and by both associations.

However, when one is reared to believe a certain way, it is not easy to change his or her opinion. Psychiatrists, psychologists and the Lord above could urge one to rethink a learned fact; however, to dispute a theory learned early in life is sometimes impossible. This unfair discrimination against homosexuals is an obstacle to their leading a normal, happy and productive life, which is the desire of gay men and lesbians, just as it is the desire of straight men and women. Research has shown a high rate of violence, as well as discrimination, against homosexuals. Just as it is with straight men, the more positive the gay male identity, the better one’s mental health will become and the higher one’s self-esteem will be. To accomplish this, the acceptance of gay men and lesbians as productive citizens, without prejudice, is necessary. Protection against violence and discrimination would not be necessary if one understood that gay men and lesbians are just like you and me; the only difference is their sexual preference.

Most scientists today agree that sexual orientation is the result of a combination of environmental, hormonal, and genetic factors. In other words, there are many factors that contribute to a person’s sexual orientation, and the factors may be different for different people.

In other words, we intend to research in depth on each factor stated and how does it affect a person’s sexual orientation then come to a conclusion if sexual orientation is genetic relating back to our topic. This is the prime objective of this project. To arrive at our objectives, we have to research about the other factors affecting sexual orientation.

Therefore, we have divided each factor into 3 subsequent chapters. Chapter 2 will be a detailed explanation on how genetic factors contribute to sexual orientation. Chapter 3 consequently will be discussing on environmental and emotional factors in relation to sexual orientation. Besides that, Chapter 4 is on the role played by hormones in determining a person’s sexual orientation. All these 3 chapters will be discussing sexual orientation on homosexuality and bisexuality.

The final chapter will relate back to our main topic which is ‘Is Sexual Orientation Genetic?’ A conclusion will be brought about based on the research, studies and evidences done on the previous 3 chapters.

Chapter 2 : Genetic Factors

Chromosomes in humans can be divided into two types which is autosomes and sex chromosomes. The sex chromosomes contain certain genetic traits link to a person’s sex. It can be XX with phenotype female and XY with phenotype male. On the other hand, the autosomes contain the rest of the genetic hereditary information. Both autosomes and sex chromosomes act in the same way during cell division. There are 23 pairs of chromosomes of which 22 pairs of autosomes and 1 pair of sex chromosome giving a total of 46 per cell for one human. A person’s sex is determined by the sex chromosome (wiki chromosome).

Based on a research conducted by scientists on November 8th 2007, new evidences have been uncovered showing genetics has a role to play in determining whether an individual is homosexual or heterosexual. Dr. Sandra Witelson, a neuroscientist in the Michael G. DeGroote School of Medicine at McMaster University, and colleges at Sunnybrook Health Sciences Centre in Toronto conducted the research on studies of the brains of healthy, right handed, 18 to 35- year old homosexual and heterosexual men using magnetic resonance imagining (MRI). About 10 years ago, which is now accepted as fact, studies have demonstrated that there is a higher proportion of left-handers in the homosexual population than the general population. Consequently, in other research it was found that left-handers have a larger region of the posterior corpus callosum which is the thick band of nerve fibres connecting the two hemispheres of the brain compared to the right- handers. Furthermore, the posterior part of the corpus callosum is larger in homosexual than heterosexual men. The size of corpus callosum is largely inherited suggesting a genetic factor in sexual orientation. A correlational analysis by researchers which included size of the corpus callosum, and test scores on language, visual spatial and finger dexterity tests. Prediction on sexual orientation in 95 per cent of the cases was done by using all these variables.

A report by the National Cancer Institute researchers states that the appearance that many homosexual men inherit a gene from their mothers that influences sexual orientation. It was suggested that inherited genetic factors at least play a role in determining sexual orientation. The study’s lead author Dean Hamer, chief of the cancer institute’s section on Gene Structure and regulation concluded that it is basically not a choice or a decision to be a gay. However, people have no control over the genes inherited and there is no way to change it. The family histories of 114 gay men were studied and it was found that more homosexual brothers, uncles and male cousins than would be expected in the general population whereby some families had three generations of homosexual relatives. It was suggested that something inherited was going on since the uncles and cousins were not raised in the same household but do share genetic information.

Following up another studies was made on the DNA from 40 pairs of homosexual brothers and it was found that 33 of them shared same genetic markers on the X chromosome in a region known as Xq28. The X chromosomes are always inherited from mothers. Genes consist of tiny coils of DNA, deoxyribonucleic acid, which carries the instructions to manufacture a particular body substance. No such similar sharing was present in the same region among heterosexual men. It is expected that this region will be important for both heterosexual and homosexual development providing very small and subtle difference between the genes of each group. However, the finding does not explain all homosexuality. Seven out of 40 pairs of homosexual brothers studied did not have the common genetic factor.

Part of the studies state that the cancer Kaposi’s sarcoma unusually afflicts large numbers of homosexuals. Further study is being conducted to determine whether a similar genetic link occurs in families of homosexual women hoping to identify the specific gene involved in sexual orientation.

Gregory King, spokesman for the Human Rights Campaign Fund, a gay and lesbian activist group, said he hoped from the studies it would help Americans understand that most lesbian and gay people do not choose their sexual orientation. Despite, concerns are there among people who are lesbians and gay that this discovery will be misused to suggest that homosexuality is something that needs to be corrected.

According to the variation in sexual orientation, heritability studies have differed on the precise contribution of genetics, though a few linkage studies have indicated a possible role for certain genes on the X chromosome. However, the strength of that evidence is limited due to the conflicting nature of the reports and small sample sizes. Some of the questions in relation to the possible genetic underpinnings of sexual orientation have been clarified by a more recent study conducted by the first ever genome-wide association study (GWAS) on sexual orientation. It is also in relation to the release of a web-based survey to the large 23andMe database of over 180,000 individuals.

Furthermore, the other non-genetic phenotypes associated with sexual orientation are also explored. The objective is to understand the relationship between sexual orientation and non-genetic phenotypes as the data collected was extracted from dozens of 23andMe surveys taking into consideration thousands of conditions and trait. Research has shown that lesbians are more likely than heterosexual women to have alcoholism and alcohol-related problems (3). A number of studies have also found that women with same sex partners are more likely to have psychiatric disorders, including major depression (4) and men with same sex partners are more likely to have anxiety and mood disorders (5).

Phenotype analyses were conducted using linear or logistic regression. In statistics, linear regression is the relationship between a scalar dependent variable Y and one or more explanatory variables denoted X as the data modelled using linear predictor functions, and unknown model parameters are estimated from the data. Logistic regression is a type of analysis used to predict the outcome of a categorical dependent variable based on one or more predictor variables that is used in estimating empirical values of the parameters in a qualitative response model(wiki). The reported betas are the change on the sexual identity scale per unit of the other phenotype. Both the phenotype analyses and GWAS analyses controlled for age, the first five principal components, and attitudes towards homosexuality as collected in the Sexual Orientation Survey. GWAS analyses were conducted in individuals of European descent.

The questions asked for this study to over 23,000 individuals 23andMe database is as follows:

The survey counts based on the questions asked were as below:

They have examined the correlation between sexual identity and ~1000 phenotypes already characterized in the 23andMe database through other surveys. These analyses were preliminary as outliers or confounders beyond what is listed in the methods were not checked. Previous ¬ndings were replicated showing a positive association between lesbians and alcoholism, and between lesbians and gay men and several psychiatric conditions.

Chapter 3 : Environmental and Emotional Factors

On the development of human sexual orientation, another possible factor is the environmental and emotional influences. Many influences or factors lead to sexual orientation but no findings have emerged that permit scientists to conclude that sexual orientation is determined by any particular factor or factors. Therefore, a great deal of people thinks nature and nurture both play complex roles (wiki environment sexual orientation).

Environmental factors are associated with family influences. Evidence have been provided by researches that gay men report having had less loving and more rejecting fathers, and closer relationships with their mothers, than non-gay men. Some researchers think this may indicate that childhood family experiences are important determinants to homosexuality, or that parents behave this way in response to gender-variant traits in a child. Both possibilities might be true in different cases (wiki).

Childhood factors do affect marital choices as children who experience parental divorce are less likely to marry heterosexually than those growing up in intact families. In a broad point of view, heterosexual marriage was significantly linked to having young parents, small age differences between parents, stable parental relationships, large sibships (a group of offspring having the same two parents) , and late birth order. For men, homosexual marriage was associated with having older mothers, divorced parents, absent fathers, and being the youngest child. On the other hand, for women, maternal death during adolescence and being the only or youngest child or the only girl in the family increased the likelihood of homosexual marriage. Childhood family experiences are important determinants of heterosexual and homosexual marriage decisions in adulthood (http://link.springer.com/article/10.1007%2Fs10508-006-9062-2).

Consequently, parental sexual orientation may affect child development. Studies were focused on an early research on children with lesbian and gay parents in which the children had been born in the context of a heterosexual marriage. The developments among children of divorced lesbian mothers were compared with children of divorced heterosexual mothers and few significant differences were found. Children in the research who had been born into homes with married mothers and fathers have no obvious reasons to understand on their healthy development as the children faced early exposure to apparently heterosexual male and female role models which mainly contributes to the healthy development.

In comparison, a study conducted by Charlotte J. Patterson from University of Virginia on lesbian or gay parents who rear infants and children from offspring and it is important that the children had never lived with heterosexual parents. The study was on a group of 4 to 9 year old children who had been born to or adopted early in life by lesbian mothers. Results from in-home interviews and also from questionnaires showed that children had regular contact with a wide range of adults of both genders, both within and outside of their families. The children’s self-concepts and preferences for same-gender playmates and activities were much like those of other children their ages. Moreover, standardized measures of social competence and of behaviour problems, such as those from the Child Behaviour Checklist (CBCL), showed that they scored within the range of normal variation for a representative sample of same-aged American children. Therefore, it was clear from this study and others like it that it was quite possible for lesbian mothers to rear healthy children.

Consistent with earlier findings, results from the study revealed few differences in adjustment between adolescents living with same-sex parents and those living with opposite-sex parents . There were no significant differences between teenagers living with same-sex parents and those living with other-sex parents on self-reported assessments of psychological well-being, such as self-esteem and anxiety, measures of school outcomes, such as grade point averages and trouble in school, or measures of family relationships, such as parental warmth and care from adults and peers. Adolescents in the two groups were equally likely to say that they had been involved in a romantic relationship in the last 18 months, and they were equally likely to report having engaged in sexual intercourse. The only statistically reliable difference between the two groups is that those with same-sex parents felt a greater sense of connection to people at school compared to the youngsters living with same-sex couples. There were no significant differences in self-reported substance use, delinquency, or peer victimization between those reared by same or other-sex couples.

Although the gender of parents’ partners was not an important predictor of adolescent well-being, other aspects of family relationships were significantly associated with teenagers’ adjustment. Consistent with other findings about adolescent development, the qualities of family relationships rather than the gender of parents’ partners were consistently related to adolescent outcomes. Parents who reported having close relationships with their offspring had adolescents who reported more favourable adjustment.

The fact that children of lesbian mothers generally develop in healthy ways should not be taken to suggest that no challenges were encountered. Many investigators have remarked upon the fact that children of lesbian and gay parents may encounter anti-gay sentiments in their daily lives. For example, in a study of 10- year-old children born to lesbian mothers, Gartrell, Deck, Rodas, Peyser, and Banks (2005) reported that a substantial minority had encountered anti-gay sentiments among their peers. Those who had such encounters were likely to report having felt angry, upset, or sad about these experiences. Children of lesbian and gay parents may be exposed to prejudice against their parents in some settings, and this may be painful for them, but evidence for the idea that such encounters affect children’s overall adjustment is lacking.

Another study, published in the October 2006 issue of Archives of Sexual Behaviour, authored by Danish epidemiologist Morten Frisch and statistician Anders Hviid, reports the analysis of data from over two million men and women. It is the first study to examine an entire group of homosexuals for environmental factors in their decisions to marry homosexually. The research suggests a link between environmental factors such as geographic birthplace and family relationships and the probability of marrying a same-sex or opposite-sex partner. The massive study also finds that the number of brothers and sisters increases the probability of marrying heterosexually. This finding questions a recent, widely touted Canadian study of birth order that found the number of older brothers increased the probably of homosexuality in men.

The researchers found for each additional year one’s parents stay married, the probability of heterosexual marriage in the children increased by 1.6% among sons and 1.0% among daughters. In contrast, the rate of homosexual unions decreased by 1.8% among sons and 1.4% among daughters for every year of intact parental marriage. Summing these effects over years of childhood and adolescence contributes to a noteworthy impact.

Regarding homosexual marriages, researchers have also found that birth place relates to the sexual orientation of marriage partner. Being born in urban settings increased the probability of homosexual marriage and decreased the probability of heterosexual marriage. This study was said to be the first to show that birth place or some correlate thereof influences marital choices in adulthood.

The researchers also confirmed previous research suggesting that children who experience parental divorce are less likely to marry heterosexually than children reared in intact families. For men, unknown paternal identity, parental divorce, short duration of cohabitation with both parents, and long duration of father-absent cohabitation with mother were all associated with increased rates of homosexual marriage. For women, homosexual marriage rates were elevated among women whose parents were married briefly, and those who experienced long periods of mother absence due either to abandonment or death during the teen years.

Taken together, the study’s findings suggest that intact parents bearing multiple children and living in rural areas increase the probability of heterosexual pairings in their children. The study was not designed to examine all possible contributions to sexual orientation nor does it account for individual situations. We know, for instance, that gays and straights come from all kinds of families and locations. However, the study raises the possibility that family and social factors function to help shape adult sexual orientation.

Chapter 4: Hormonal Factors

Hormones are your body’s chemical messengers. It is released by one or more cells which travel through the bloodstream that affects cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In relation to sexuality following up the hormonal theory, exposure to certain hormones plays an act in fetal sex differentiation. Besides that, this exposure also influences the sexual orientation that emerges later in the adult.

Hormones which interact with the developing brain cells coming from the differences in brain structure are accredit to be the basis of sex differences in countless behaviour, including sexual orientation. The interaction of these hormones on the developing brain is affected by prenatal factors that can influence later the sex-typed behaviour in children.

Factors hypothesized in contributing to sex-typed behaviour concerns the same as those hypothesized to contribute to sexual orientation. Higher rates of sex-atypical behaviour in childhood and adulthood are seen in homosexual men and women compared to the same sex heterosexuals. Early hormones have been suggested to influence both sexual orientation and related childhood sex-typed behaviours. Recent studies, however, have provided evidence in support of prenatal androgen exposure influencing childhood sex-typed behaviour.

An example of the study is Early Hormonal Influences on Childhood Sex-Typed Activity and Playmate Preferences: Implications for the Development of Sexual Orientation. The hormonal influences on activity and playmate preferences in children with congenital adrenal hyperplasia (CAH) are examined. The children were in the range of ages between 2.5 to 12 years. It is observed that CAH girls preferred boys’ toys and activities and had greater preference for boy playmates than controls. On the other hand, CAH boys did not differ significantly from controls and activity and playmate preferences were not related. From this it was concluded that early androgen has a major effect on childhood activity preferences but only a weak influence on playmate preferences. Besides that, sex segregation does not arise from sex-typed activity preferences, activity and playmate preferences may be differently predictive of sexual orientation and hormonal influences on sexual orientation are likely to be complex.

Consequently, prospective and retrospective studies of childhood gender role behaviour reveal homosexual males to be more likely than heterosexual males in the sense of participating in girls’ games, to experiment with cosmetics and jewellery and to be less likely than heterosexual males to participate in sports. In the same way, lesbians analytical report shows that they were more likely than heterosexual females in the manner of participating in sports, to be called a tomboy and to be less likely than heterosexual females as in experimenting with or using cosmetics and jewellery or even to wear dresses. From reports by Bailey & Zucker, it was also known that homosexual men and women played with opposite sex playmates in childhood more that did heterosexual men and women.

However, the differences between homosexual and heterosexual individuals may not be confined to childhood activities. For example, in another report by McCormick & Witelson, it is stated that heterosexual men have higher spatial ability and lower verbal ability compared to both homosexual men and heterosexual women. Besides that, a higher rate of left-handedness has been noticed in both homosexual men and women than heterosexual comparisons.

Nonetheless, it is important to note that there are a few other sex-typed behaviours not related to sexual orientation. This is identified as most homosexual men and women have typical gender identity and are similar to same sex heterosexual individuals on aspects of mating psychology related to sexual selection that show sex differences, for example, interest in uncommitted sex. These comparisons are useful because sexual orientation differences that parallel sex differences suggest that some of the factors that cause sex differences also cause differences between homosexual and heterosexual individuals of the same sex. This is because some homosexual individuals are as sex-typical as most heterosexuals, there may be more than one cause of sexual orientation. On the other hand, when sexual orientation differences do not parallel sex differences, different etiologies are likely.

Gonadal hormones have been hypothesized to play a main role in the development of sex-typed behaviour and sexual orientation. Thus, high levels of androgen during sensitive periods of development have been suggested to produce masculine-typical behaviour, including childhood activities, cognitive abilities, and sexual orientation directed to women, that is, male heterosexuality and female homosexuality, whereas very low levels of androgen during those periods are hypothesized to result in female typical childhood activities, cognitive abilities, and sexual orientation directed to men, that is, male homosexuality and female heterosexuality.

Human sex-typed behaviour is also affected by early exposure to hormones. Thus, female participants with congenital adrenal hyperplasia (CAH), who have high levels of androgen during the prenatal and early postnatal periods, have greater preference for traditionally masculine toys and activities, higher spatial ability, and greater rates of homosexual or bisexual fantasies than controls. Similarly, female participants exposed to high levels of masculinizing or defeminizing hormones as a result of maternal ingestion during pregnancy have been reported to be more aggressive and to have higher rates of homosexual or bisexual fantasies than controls. These increases in male typical behaviour which occur in the presence of female gender identity in both CAH girls and women and those with exogenous hormone exposure.

Unusual hormone exposure in boys and men has complex relationships to behaviour. In relation, low androgen seems to result in reduced male typical behaviour. Male adolescents and adults with deficient androgen beginning early in life have shown reduced spatial ability compared with controls. High levels of masculinizing hormones have been associated with increased, decreased, and unchanged masculine typical behaviour. Male participants exposed to androgenizing progestin have been reported to be more aggressive than their brothers, but male participants with CAH and thus high levels of androgen generally show male typical behaviour. There are few systematic studies of sexual behaviour in men with unusual early hormone exposure, but homosexuality may be more common in men who are assumed to have low prenatal testosterone, for example, XXY men.

There is evidence especially in female individuals that early hormone exposure affects both sexual orientation and some of the behaviors that are related to it, providing indirect support for the hypothesis that sexual orientation typically is influenced b

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