General aspects[ edit ] Often, sexual orientation and sexual orientation identity are not distinguished, which can impact accurately assessing sexual identity and whether or not sexual orientation is able to change; sexual orientation identity can change throughout an individual's life, and may or may not align with biological sex, sexual behavior or actual sexual orientation.
Innate bisexuality Innate bisexuality is an idea introduced by Sigmund Freud. According to this theory, all humans are born bisexual in a very broad sense of the term, that of incorporating general aspects of both sexes. In Freud's view, this was true anatomically and therefore also psychologically, with sexual attraction to both sexes being one part of this psychological bisexuality. Freud believed that in the course of sexual development the masculine side would normally become dominant in men and the feminine side in women, but that as adults everyone still has desires derived from both the masculine and the feminine sides of their natures.
Freud did not claim that everyone is bisexual in the sense of feeling the same level of sexual attraction to both genders. To date, a lot of research has been conducted to determine the influence of genetics, hormonal action, development dynamics, social and cultural influences—which has led many to think that biology and environment factors play a complex role in forming it.
It was once thought that homosexuality was the result of faulty psychological development, resulting from childhood experiences and troubled relationships, including childhood sexual abuse. It has been found that this was based on prejudice and misinformation.
Biology and sexual orientation Research has identified several biological factors which may be related to the development of sexual orientation, including genes , prenatal hormones , and brain structure. No single controlling cause has been identified, and research is continuing in this area. Current scientific investigation usually seeks to find biological explanations for the adoption of a particular sexual orientation. A twin study from appears to exclude genes as a major factor,  while a twin study from found that homosexuality was explained by both genes and environmental factors.
The authors concluded that "our findings, taken in context with previous work, suggest that genetic variation in each of these regions contributes to development of the important psychological trait of male sexual orientation. Prenatal hormones and sexual orientation The hormonal theory of sexuality holds that just as exposure to certain hormones plays a role in fetal sex differentiation , hormonal exposure also influences the sexual orientation that emerges later in the adult.
Fetal hormones may be seen as either the primary influence upon adult sexual orientation or as a co-factor interacting with genes or environmental and social conditions. The default developmental pathway for a human fetus being female, the Y chromosome is what induces the changes necessary to shift to the male developmental pathway.
This differentiation process is driven by androgen hormones, mainly testosterone and dihydrotestosterone DHT. The newly formed testicles in the fetus are responsible for the secretion of androgens, that will cooperate in driving the sexual differentiation of the developing fetus, including its brain. This results in sexual differences between males and females. Fraternal birth order and sexual orientation Recent studies found an increased chance of homosexuality in men whose mothers previously carried to term many male children.
This effect is nullified if the man is left-handed. However, research suggests that this may be of immunological origin, caused by a maternal immune reaction against a substance crucial to male fetal development during pregnancy, which becomes increasingly likely after every male gestation. As a result of this immune effect, alterations in later-born males' prenatal development have been thought to occur. This process, known as the maternal immunization hypothesis MIH , would begin when cells from a male fetus enter the mother's circulation during pregnancy or while giving birth.
These Y-linked proteins would not be recognized in the mother's immune system because she is female, causing her to develop antibodies which would travel through the placental barrier into the fetal compartment.
From here, the anti-male bodies would then cross the blood—brain barrier of the developing fetal brain, altering sex-dimorphic brain structures relative to sexual orientation, causing the exposed son to be more attracted to men over women.
Environment and sexual orientation There is no substantive evidence to support the suggestion that early childhood experiences, parenting, sexual abuse, or other adverse life events influence sexual orientation. However, studies do find that aspects of sexuality expression have an experiential basis and that parental attitudes towards a particular sexual orientation may affect how children of the parents experiment with behaviors related to a certain sexual orientation.
A variety of theories about the influences on sexual orientation have been proposed. Sexual orientation probably is not determined by any one factor but by a combination of genetic, hormonal, and environmental influences. In recent decades, biologically based theories have been favored by experts. Although there continues to be controversy and uncertainty as to the genesis of the variety of human sexual orientations, there is no scientific evidence that abnormal parenting, sexual abuse, or other adverse life events influence sexual orientation.
Current knowledge suggests that sexual orientation is usually established during early childhood. However, the available evidence indicates that the vast majority of lesbian and gay adults were raised by heterosexual parents and the vast majority of children raised by lesbian and gay parents eventually grow up to be heterosexual. The Royal College of Psychiatrists in stated: It would appear that sexual orientation is biological in nature, determined by a complex interplay of genetic factors and the early uterine environment.
Sexual orientation is therefore not a choice, though sexual behaviour clearly is. The American Psychiatric Association stated: Homosexuality was once thought to be the result of troubled family dynamics or faulty psychological development.
Those assumptions are now understood to have been based on misinformation and prejudice. The evaluation of amici is that, although some of this research may be promising in facilitating greater understanding of the development of sexual orientation, it does not permit a conclusion based in sound science at the present time as to the cause or causes of sexual orientation, whether homosexual, bisexual, or heterosexual.
Efforts to change sexual orientation[ edit ] Main articles: Sexual orientation change efforts and Conversion therapy Sexual orientation change efforts are methods that aim to change a same-sex sexual orientation. They may include behavioral techniques, cognitive behavioral therapy , reparative therapy , psychoanalytic techniques, medical approaches, and religious and spiritual approaches. Efforts to change sexual orientation are unlikely to be successful and involve some risk of harm, contrary to the claims of SOCE practitioners and advocates.
Even though the research and clinical literature demonstrate that same-sex sexual and romantic attractions, feelings, and behaviors are normal and positive variations of human sexuality, regardless of sexual orientation identity , the task force concluded that the population that undergoes SOCE tends to have strongly conservative religious views that lead them to seek to change their sexual orientation. Thus, the appropriate application of affirmative therapeutic interventions for those who seek SOCE involves therapist acceptance, support, and understanding of clients and the facilitation of clients' active coping, social support, and identity exploration and development, without imposing a specific sexual orientation identity outcome.
The Pan American Health Organization further called on governments, academic institutions, professional associations and the media to expose these practices and to promote respect for diversity. The World Health Organization affiliate further noted that gay minors have sometimes been forced to attend these "therapies" involuntarily, being deprived of their liberty and sometimes kept in isolation for several months, and that these findings were reported by several United Nations bodies.
Additionally, the Pan American Health Organization recommended that such malpractices be denounced and subject to sanctions and penalties under national legislation, as they constitute a violation of the ethical principles of health care and violate human rights that are protected by international and regional agreements. Early classification schemes[ edit ] One of the earliest sexual orientation classification schemes was proposed in the s by Karl Heinrich Ulrichs in a series of pamphlets he published privately.
An urning can be further categorized by degree of effeminacy. These categories directly correspond with the categories of sexual orientation used today: In the series of pamphlets, Ulrichs outlined a set of questions to determine if a man was an urning.
The definitions of each category of Ulrichs' classification scheme are as follows: Dioning - Comparable to the modern term "heterosexual" Urning - Comparable to the modern term "homosexual" Mannling - A manly urning Zwischen - A somewhat manly and somewhat effeminate urning Virilised - An urning that sexually behaves like a dioning Urano-Dioning - Comparable to the modern term "bisexual" From at least the late nineteenth century in Europe, there was speculation that the range of human sexual response looked more like a continuum than two or three discrete categories.
Berlin sexologist Magnus Hirschfeld published a scheme in that measured the strength of an individual's sexual desire on two independent point scales, A homosexual and B heterosexual.
Males do not represent two discrete populations, heterosexual and homosexual. The world is not to be divided into sheep and goats. Not all things are black nor all things white The living world is a continuum in each and every one of its aspects. The sooner we learn this concerning human sexual behavior, the sooner we shall reach a sound understanding of the realities of sex. The Kinsey scale provides a classification of sexual orientation based on the relative amounts of heterosexual and homosexual experience or psychic response in one's history at a given time.
The position on the scale is based on the relation of heterosexuality to homosexuality in one's history, rather than the actual amount of overt experience or psychic response.
An individual can be assigned a position on the scale in accordance with the following definitions of the points of the scale: Individuals make no physical contact which results in erotic arousal or orgasm and make no psychic responses to individuals of their own sex.
Individuals have only incidental homosexual contacts which have involved physical or psychic response or incidental psychic response without physical contact. Individuals have more than incidental homosexual experience or respond rather definitely to homosexual stimuli. Individuals are about equally homosexual and heterosexual in their experiences or psychic reactions.
Individuals have more overt activity or psychic reactions in the homosexual while still maintaining a fair amount of heterosexual activity or responding rather definitively to heterosexual contact. Individuals are almost entirely homosexual in their activities or reactions. Individuals who are exclusively homosexual, both in regard to their overt experience and in regard to their psychic reactions.
The Kinsey scale has been praised for dismissing the dichotomous classification of sexual orientation and allowing for a new perspective on human sexuality. However, the scale has been criticized because it is still not a true continuum. Despite seven categories being able to provide a more accurate description of sexual orientation than a dichotomous scale, it is still difficult to determine which category individuals should be assigned to.
In a major study comparing sexual response in homosexual males and females, Masters and Johnson discuss the difficulty of assigning the Kinsey ratings to participants. They report finding it difficult to assign ratings for individuals with a large number of heterosexual and homosexual experiences.
When there are a substantial number of heterosexual and homosexual experiences in one's history, it becomes difficult for that individual to be fully objective in assessing the relative amount of each.
Valuable information was lost by collapsing the two values into one final score. A person who has only predominantly same sex reactions is different from someone with relatively little reaction but lots of same sex experience. It would have been quite simple for Kinsey to have measured the two dimensions separately and report scores independently to avoid loss of information. Furthermore, there are more than two dimensions of sexuality to be considered.
Beyond behavior and reactions, one could also assess attraction, identification, lifestyle etc. This is addressed by the Klein Sexual Orientation Grid. A third concern with the Kinsey scale is that it inappropriately measures heterosexuality and homosexuality on the same scale, making one a tradeoff of the other. However, if they are considered as separate dimensions one can be simultaneously very masculine and very feminine. Similarly, considering heterosexuality and homosexuality on separate scales would allow one to be both very heterosexual and very homosexual or not very much of either.
When they are measured independently, the degree of heterosexual and homosexual can be independently determined, rather than the balance between heterosexual and homosexual as determined using the Kinsey Scale. Klein Sexual Orientation Grid In response to the criticism of the Kinsey scale only measuring two dimensions of sexual orientation, Fritz Klein developed the Klein sexual orientation grid KSOG , a multidimensional scale for describing sexual orientation.
Introduced in Klein's book The Bisexual Option , the KSOG uses a 7-point scale to assess seven different dimensions of sexuality at three different points in an individual's life: The Sell Assessment of Sexual Orientation[ edit ] The Sell Assessment of Sexual Orientation SASO was developed to address the major concerns with the Kinsey Scale and Klein Sexual Orientation Grid and as such, measures sexual orientation on a continuum, considers various dimensions of sexual orientation, and considers homosexuality and heterosexuality separately.
Rather than providing a final solution to the question of how to best measure sexual orientation, the SASO is meant to provoke discussion and debate about measurements of sexual orientation. Six of these questions assess sexual attraction, four assess sexual behavior, and two assess sexual orientation identity.
For each question on the scale that measures homosexuality there is a corresponding question that measures heterosexuality giving six matching pairs of questions.
Taken all together, the six pairs of questions and responses provide a profile of an individual's sexual orientation. However, results can be further simplified into four summaries that look specifically at responses that correspond to either homosexuality, heterosexuality, bisexuality or asexuality.
Identity and behavior are measured as supplemental information because they are both closely tied to sexual attraction and sexual orientation.
Major criticisms of the SASO have not been established, but a concern is that the reliability and validity remains largely unexamined.