Sexual orientation refers to the sex, sexes, gender or genders, to which a person is attracted and which form the focus of a person’s amorous or erotic desires, fantasies, and spontaneous feelings. The alternative terms sexual preference and sexual inclination have similar meanings. Clinicians and those who believe sexuality is fixed early in life tend to use the former term; those believing sexuality is fluid and reflects preference and choice tend towards the latter terms.
Typically a person may be identified as primarily heterosexual (the focus is primarily people of the opposite sex), homosexual (people of the same sex), bisexual (potentially both or either sexes), or asexual (no sexual desire for either sex). (But compare Homosexuality and transgender for a discussion on the use of homo- and heterosexual when referring to transgender or intersex people.)
The term sexual orientation may also refer to the “identity” of a person, either by choice or as an expression of an inner attribute.
These categories are also used to describe sexual behaviour, which may depart from an individual’s chosen identity or spontaneous desires.
“Sexual orientation“ is also a legal term that has a meaning developed through case law that is separate from the meaning used in other fields. It is the most common term used in laws that prohibit discrimination based on homosexuality, heterosexuality and bisexuality.
Classification of individuals into these groups is controversial, and different observers may prefer orientation, behaviour, or self-identification as the sorting criterion, and make different judgments as to degree.
A much wider definition of sexual orientation
Typically a person may be identified as primarily heterosexual (the focus is primarily people of the opposite sex/gender), homosexual (people of the same sex/gender), bisexual (potentially both or either sexes/gender), or asexual (no sexual attraction for either sex/gender).
There is sometimes an overlap of opinion as to whether a person is straight/bisexual or gay/bisexual because such a person is technically bisexual (sexually and romantically attracted to both sexes/genders), but also fits a looser, un-official definition of homosexual (gay/lesbian) or straight/heterosexual as being primarily attracted to the same or opposite sex/gender.
However, this categorization ignores many issues of individuality and culture, and sexuality itself has many different facets. Therefore, even when it seems obvious, identifying sexual orientation is often not as simple as it seems.
Terminology about sexual orientation is further complicated by the distinction between sex and gender. Scholars usually make a distinction between sex, the quality of being biologically male, female, or intersex, and gender, a person’s socially defined role as male, female, or neither. Some definitions of “sexual orientation” use both concepts; others use only one. The American Psychological Association and others define sexual orientation strictly in terms of biological sex; whereas sociologist Rodriguez Rust (2000) and others argue for a more multifaceted definition:
“…Most alternative models of sexuality…define sexual orientation in terms of dichotomous biological sex or gender…. Most theorists would not eliminate the reference to sex or gender, but instead advocate incorporating more complex non-binary concepts or sex or gender, more complex relationships between sex, gender, and sexuality, and/or additional non-gendered dimensions into models of sexuality.”
Complexities and terminology
Many people in Western societies today speak of sexual orientation as a unified and actual thing. Over the past thirty years some anthropologists, historians, and literary critics have pointed out that it in fact comprises a variety of different things, including a specific object of erotic desire, and forms of erotic fulfillment (i.e. sexual behaviors).
Sexual orientation, identity, and behaviour
Some examples may help clarify the distinctions between orientation or desire, identity, and behaviour:
- People of any sexual orientation may choose sexual abstinence, suppressing or ignoring any desires they may have.
- Some people who feel homosexual desire may engage in heterosexual behaviour and even heterosexual marriage for a number of reasons, whether cultural or religious beliefs, or through fear of discrimination should they “come out”.
- Some bisexual people have only one sexual or romantic partner at a time, and sometimes happen to have sexual and romantic partners from one only gender throughout their entire lives, despite attraction to some people of both sexes.
- People with heterosexual attractions may nonetheless have homosexual encounters whether by self-initiation, with initiation by the other party, with multiple simultaneous partners, through acts of deception, or due to absence of an available partner of the opposite gender (see e.g. prison sex) or other unusual social circumstances.
- A minority of people who self-identify as heterosexual or homosexual actually feel attracted to and engage in sexual behaviour with people of both genders.
Some new terminology consciously differentiates between these three aspects. For example, men who have sex with men, or “MSM”, is a clinical term used to describe behavior only. Same-sex attraction focuses on feelings and desires.
Terms such as straight, gay, and lesbian tend to be used more often as identity-labels, but are sometimes used as synonyms for heterosexual, homosexual (men and women or just men), and homosexual (women), respectively. (See also: Terminology of homosexuality.)
Note that the term “sexual identity” is also sometimes intended to mean a person’s conception of one’s own sex or gender identity. This use however is considered highly inaccurate by transgender people, who consider their gender identity to be related to, but separate from their sexual orientation/identity.
In his book The Bisexual Option, Dr. Fritz Klein, MD, proposes an even more complicated description of sexual orientation. The “Klein Sexual Orientation Grid” takes into account sexual attraction, sexual behavior, sexual fantasies, emotional and social partners, lifestyle, and self-identification. Each of these axes is also considered for the personal past, present, and ideal. Klein Sexual Orientation Grid.
Classification and boundaries
There is a common boundary-drawing problem (or controversy, at least) when considering how to divide a population between “heterosexual”, “bisexual”, and “homosexual” by behaviour or by orientation. The largest disagreement is probably over which criterion – identity, desire, or behavior – is most important.
With regard to identity, common controversial topics of procedure include whether someone should be categorized as “bisexual” by behavior if they have any sexual contact with members of more than one gender, and further, whether frequency of contact with either sex is a factor, whether group sex is admissible as an instance, and whether the occurrence of orgasm, as well as its frequency in terms of total encounters, has any bearing.
When classifying by orientation or desire, controversial topics include the breadth of attraction to both genders, what “intensity” of attraction is admissible, and whether self-reporting should be solely trusted or whether there should be any manner of “objective” measure.
Some observers only consider the two poles (same-sex vs. opposite-sex), others set explicit but somewhat arbitrary boundaries for the middle “box” when precision is required. Many, following the view of the noted sex researcher Alfred Kinsey|Dr. Alfred Kinsey (see Kinsey scale), view sexual orientation and behavior on a spectrum, from exclusively homosexual to exclusively heterosexual, with continuous or discontinuous gradations in between. Kinsey’s work has generally replaced Freud’s much different theory of innate bisexuality, which was based on erroneous assumptions about human biology.
Several objections have been raised to the classification of people based on desire, including:
- Sexual attraction is about more than gender; many individual attributes are also important, sometimes more important.
- Sexual behaviour is a changeable choice, not a fixed attribute of identity by which one should be classified.
- Category boundaries are arbitrary, and it’s demeaning to try to fix complex people into simple “boxes”.
- Labels interfere with accepting people for who they are and who they love.
This situation is complicated further by the fact that there are several different biological and psychosocial components to gender, and a given person may not cleanly fit into a particular category. Some people even find the notion of distinct genders (and distinct sexual orientations based upon them) to be offensive. The complexities of gender are explained in the article on sex.
“Alternative” sexual orientations
Some people (often labeled “bisexuals”) label themselves pansexual, in that they are attracted to people who don’t fit in a clearly definable sex/gender (e.g., transgender and/or intersex people). Still other people use varied terms to describe their sexual orientations, including: fluid (especially when they don’t want to restrict their sexual orientation with a more-specific label), homoflexible (for people who consider themselves predominantly homosexual but occasionally open to opposite-sex attraction), heteroflexible (the opposite) and sapiosexual (attracted to someone’s mind as much as their body). Additionally, other people (including Kinsey) argue that asexuality best characterised a segment of the population and should be regarded as its own orientation.
Sexual fetishism is usually considered orthogonal (unrelated) to the gender-based categories of sexual orientation listed above, though of course it may in some cases be an important part of a person’s sexual identity and behaviour.
Some people feel that various forms of “paraphilia“, such as sexual attraction to animals (zoophilia), prepubescent children (pedophilia), or inanimate objects, are “alternative” sexual orientations to those listed above. Others argue that these classifications are orthogonal. (See Other for research.)
Hani Miletski Ph.D., a sexologist and author, argues that zoosexuality was a full sexual orientation by the same criteria that other sexual orientations met:
“Chapter 13 repeats and summarises the answer to the basic research question in the current study – is there a sexual orientation toward animals? The definition of “sexual orientation” was adapted from Francoeur (1991) in his discussion of homosexuality, heterosexuality, and bisexuality. According to this definition, sexual orientation consists of three interrelated aspects:
- Affectional orientation – who or what we bond with emotionally;
- Sexual fantasy orientation – about whom or what we fantasise; and
- Erotic orientation – with whom or what we prefer to have sex.
and concludes that all three criteria are met.”
“Chapter 15 compares my findings with Kinsey et al.’s (1948) study on the sexual behaviours of American men, Kinsey et al.’s (1953) study on the sexual behaviours of American women, the Gebhard et al.’s (1965) study on sex offenders, the Hunt survey (1974), Peretti and Rowan’s (1983) study, and Donofrio’s (1996) doctoral dissertation.”
Some people use the term queer as an umbrella term to include homosexuality and bisexuality (as well as transgender and often intersex people), often as well as fetishism, non-human sexual attraction, and/or other “paraphilia”, but it may also be used more narrowly. It is also varyingly used as a derogatory term and as a term of pride.
Demographics of sexual orientation
The multiple aspects of sexual orientation and the boundary-drawing problems already described create methodological challenges for the study of the demographics of sexual orientation. Determining the frequency of various sexual orientations in real-world populations is difficult and controversial.
In the oft-cited and oft-criticized Sexual Behavior in the Human Male (1948) and Sexual Behavior in the Human Female (1953), by Alfred C. Kinsey et. al., people were asked to rate themselves on a scale from completely heterosexual to completely homosexual. Kinsey reported that when the individuals’ behavior as well as their identity are analyzed, most people appeared to be at least somewhat bisexual – i.e., most people have some attraction to either sex, although usually one sex is preferred.
According to Kinsey, only a minority (5-10%) can be considered fully heterosexual or homosexual. Conversely, only an even smaller minority can be considered fully bisexual (with an equal attraction to both sexes). Kinsey concluded that there are not “two discrete populations, heterosexual and homosexual…. Only the human mind invents categories and tries to force facts into pigeonholes. The living world is a continuum in each and every one of its aspects…”
Kinsey’s methods have been criticized as flawed, particularly with regard to the randomness of his sample population, which included a large number of prison inmates. Nevertheless, Paul Gebhard, subsequent director of the Kinsey Institute for Sex Research, reexamined the data in the Kinsey Reports and concluded that accounting for major statistical objections barely affected the results. Most modern scientific surveys find that the majority of people report a mostly heterosexual orientation.
However, the relative percentage of the population that reports a homosexual orientation varies with differing methodologies and selection criteria. Most of these statistical findings are in the range of 2.8 to 9% of males, and 1 to 5% of females for the United States (source: , page 24 — this figure can be as high as 12% for some large cities and as low as 1% percent for rural areas). In gay villages such as The Castro in San Francisco, California, the concentration of self-identified homosexual people can exceed 40%. Almost all of these studies have found that homosexual males occur roughly at twice the rate of homosexual females.
Estimates for the percentage of the population that identify as bisexual vary widely based on the type of questions asked. Some studies only consider a person bisexual if they are nearly equally attracted to both sexes, and others consider a person bisexual if they are at all attracted to the same sex (for otherwise mostly heterosexual persons) or to the opposite sex (for otherwise mostly homosexual persons).
A very small percentage of people are not sexually attracted to anyone (asexuality).
Causes and malleability of sexual orientation
Considerable debate continues over what biological and/or psychological variables produce sexual orientation in humans, such as genes and the exposure of certain levels of hormones to foetuses. A much smaller dialog remains in progress on whether that orientation is discretionary, largely limited to a minority of Christians and many Muslims with its foundation rooted in theology and old scientific thinking. Freud and many others, particularly in psychoanalytic traditions, speculate that formative childhood experiences (a.k.a.. nurture) help produced sexual orientation.
Most specialists follow the general conclusion of Alfred Kinsey regarding the sexual continuum, according to which a minority of humans are exclusively homosexual or heterosexual, and that the majority are bisexual, that is, that the norm is to experience a mixture homoerotic and heteroerotic feelings, each kind to a different degree. Interestingly, Kinsey himself—along with current “queer” activist groups—focus on the historicity and personal fluidity of sexual orientation. Kinsey’s studies consistently showed sexual orientation as something that evolves in many directions over a person’s lifetime.
Sexual orientation and mental health
There are at least two possible questions that can be asked about this topic: first, can people with certain sexual orientations be considered to have a mental illness, simply by virtue of their sexual orientation? Second, is there a correlation and/or a causal relationship between certain sexual orientations and any types of mental illness?
Sexual orientation as mental illness
Clinically, heterosexual acts are considered most common in today’s cultures (statistically most likely), but the concept of “normal” and “abnormal” with its connotations of sickness or moral judgment are no longer considered valid by most medical professionals.
Some Abrahamic groups maintain that homosexuals as such do not exist and that homosexuality is actually an unnatural choice, illness or addiction. Many of these groups support reparative therapy to cure homosexuality or stricter laws to prevent individuals engaging freely in homosexual activity, much in the same way as any other harmful mental illness or inappropriate aberration (which is how they tend to view it). One major advocate of this line of thought is the American National Association for Research and Therapy of Homosexuality, which rejects the consensus of the major psychological associations in removing homosexuality from the list of mental illnesses in 1973.
In 1998, the American Psychological Association stated that the psychological profession’s view on homosexuality and mental health was, “the reality is that homosexuality is not an illness. It does not require treatment and is not changeable.”
Relationship between sexual orientation and mental illness
The Journal of the American Medical Association (JAMA) reported in its January 2001 issue — citing a government-sponsored study of 5,998 adults in the Netherlands aged 18 to 64 — that “psychiatric disorders were more prevalent among homosexually active people compared with heterosexually active people. …The findings support the assumption that people with same-sex sexual behaviour are at greater risk for psychiatric disorders.” The study asserted that “the Dutch social climate toward homosexuality has long been and remains considerably more tolerant” than in other countries. 
The Gay and Lesbian Medical Association agreed in an article published July 18, 2002 by GayWired.com: “Depression and anxiety appear to affect gay men at a higher rate than in the general population. The likelihood of depression or anxiety may be greater, and the problem may be more severe for those men who remain in the closet or who do not have adequate social supports. Adolescents and young adults may be at particularly high risk of suicide because of these concerns. Culturally sensitive mental health services targeted specifically at gay men may be more effective in the prevention, early detection, and treatment of these conditions”. 
GLMA also reported a higher prevalence of substance abuse. “Gay men use substances at a higher rate than the general population…includ(ing) a number of substances ranging from amyl nitrate (‘poppers’), to marijuana, Ecstasy, and amphetamines.”
In the same article, GLMA also reported “it is still thought that gay men have higher rates of alcohol dependence and abuse than straight men” and that “recent studies seem to support the notion that gay men use tobacco at much higher rates than straight men.”