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|lesbian ∙ gay ∙ bisexual ∙ transgender|
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|Related sexual orientations|
|Attitudes and discrimination|
Bisexuality is romantic attraction, sexual attraction, or sexual behavior toward both males and females,   or to more than one sex or gender.  It may also be defined as romantic or sexual attraction to people of any sex or gender identity, which is also known as pansexuality.   
The term bisexuality is mainly used in the context of human attraction to denote romantic or sexual feelings toward both men and women,   and the concept is one of the three main classifications of sexual orientation along with heterosexuality and homosexuality, all of which exist on the heterosexual–homosexual continuum. A bisexual identity does not necessarily equate to equal sexual attraction to both sexes; commonly, people who have a distinct but not exclusive sexual preference for one sex over the other also identify themselves as bisexual. 
Scientists do not know the exact cause of sexual orientation, but they theorize that it is caused by a complex interplay of genetic, hormonal, and environmental influences,    and do not view it as a choice.    Although no single theory on the cause of sexual orientation has yet gained widespread support, scientists favor biologically-based theories.  There is considerably more evidence supporting nonsocial, biological causes of sexual orientation than social ones, especially for males.   
Bisexuality has been observed in various human societies  and elsewhere in the animal kingdom    throughout recorded history. The term bisexuality, however, like the terms hetero- and homosexuality, was coined in the 19th century. 
Sexual orientation, identity, and behavior
Bisexuality is romantic or sexual attraction to both males and females. The American Psychological Association states that "sexual orientation falls along a continuum. In other words, someone does not have to be exclusively homosexual or heterosexual, but can feel varying degrees of both. Sexual orientation develops across a person's lifetime–different people realize at different points in their lives that they are heterosexual, bisexual or homosexual."  
Sexual attraction, behavior, and identity may also be incongruent, as sexual attraction or behavior may not necessarily be consistent with identity. Some individuals identify themselves as heterosexual, homosexual, or bisexual without having had any sexual experience. Others have had homosexual experiences but do not consider themselves to be gay, lesbian, or bisexual.  Likewise, self-identified gay or lesbian individuals may occasionally sexually interact with members of the opposite sex but do not identify as bisexual.  The terms queer,  polysexual,  heteroflexible, homoflexible, men who have sex with men and women who have sex with women may also be used to describe sexual identity or identify sexual behavior. 
Some sources state that bisexuality encompasses romantic or sexual attraction to all gender identities or that it is romantic or sexual attraction to a person irrespective of that person's biological sex or gender, equating it to or rendering it interchangeable with pansexuality.   The concept of pansexuality deliberately rejects the gender binary, the "notion of two genders and indeed of specific sexual orientations",  as pansexual people are open to relationships with people who do not identify as strictly men or women.   Sometimes the phrase " bisexual umbrella" is used to describe any nonmonosexual behaviors, attractions, and identities, usually for purposes of collective action and challenging monosexist cultural assumptions. 
The bisexual activist Robyn Ochs defines bisexuality as "the potential to be attracted—romantically and/or sexually—to people of more than one sex and/or gender, not necessarily at the same time, not necessarily in the same way, and not necessarily to the same degree." 
According to Rosario, Schrimshaw, Hunter, Braun (2006):
...the development of a lesbian, gay, or bisexual (LGB) sexual identity is a complex and often difficult process. Unlike members of other minority groups (e.g., ethnic and racial minorities), most LGB individuals are not raised in a community of similar others from whom they learn about their identity and who reinforce and support that identity. Rather, LGB individuals are often raised in communities that are either ignorant of or openly hostile toward homosexuality. 
Bisexuality as a transitional identity has also been examined. In a longitudinal study about sexual identity development among lesbian, gay, and bisexual (LGB) youths, Rosario et al. "found evidence of both considerable consistency and change in LGB sexual identity over time". Youths who had identified as both gay/lesbian and bisexual prior to baseline were approximately three times more likely to identify as gay/lesbian than as bisexual at subsequent assessments. Of youths who had identified only as bisexual at earlier assessments, 60 to 70 percent continued to thus identify, while approximately 30 to 40 percent assumed a gay/lesbian identity over time. Rosario et al. suggested that "although there were youths who consistently self-identified as bisexual throughout the study, for other youths, a bisexual identity served as a transitional identity to a subsequent gay/lesbian identity." 
By contrast, a longitudinal study by Lisa M. Diamond, which followed women identifying as lesbian, bisexual, or unlabeled, found that "more women adopted bisexual/unlabeled identities than relinquished these identities," over a ten-year period. The study also found that "bisexual/unlabeled women had stable overall distributions of same-sex/other-sex attractions."  Diamond has also studied male bisexuality, noting that survey research found "almost as many men transitioned at some point from a gay identity to a bisexual, queer or unlabeled one, as did from a bisexual identity to a gay identity."  
In the 1940s, the zoologist Alfred Kinsey created a scale to measure the continuum of sexual orientation from heterosexuality to homosexuality. Kinsey studied human sexuality and argued that people have the capability of being hetero- or homosexual even if this trait does not present itself in the current circumstances.  The Kinsey scale is used to describe a person's sexual experience or response at a given time. It ranges from 0, meaning exclusively heterosexual, to 6, meaning exclusively homosexual.  People who rank anywhere from 2 to 4 are often considered bisexual; they are often not fully one extreme or the other.  The sociologists Martin S. Weinberg and Colin J. Williams write that, in principle, people who rank anywhere from 1 to 5 could be considered bisexual. 
The psychologist Jim McKnight writes that while the idea that bisexuality is a form of sexual orientation intermediate between homosexuality and heterosexuality is implicit in the Kinsey scale, that conception has been "severely challenged" since the publication of Homosexualities (1978), by Weinberg and the psychologist Alan P. Bell. 
Demographics and prevalence
Scientific estimates as to the prevalence of bisexuality have varied from 0.7% to 8%. The Janus Report on Sexual Behavior, published in 1993, concluded that 5 percent of men and 3 percent of women considered themselves bisexual, while 4 percent of men and 2 percent of women considered themselves homosexual. 
A 2002 survey in the United States by National Center for Health Statistics found that 1.8 percent of men ages 18–44 considered themselves bisexual, 2.3 percent homosexual, and 3.9 percent as "something else". The same study found that 2.8 percent of women ages 18–44 considered themselves bisexual, 1.3 percent homosexual, and 3.8 percent as "something else".  In 2007, an article in the 'Health' section of The New York Times stated that "1.5 percent of American women and 1.7 percent of American men identify themselves [as] bisexual."  Also in 2007, it was reported that 14.4 percent of young US women identified themselves as "not strictly heterosexual", with 5.6 percent of the men identifying as gay or bisexual.  A study in the journal Biological Psychology in 2011 reported that there were men who identify themselves as bisexuals and who were aroused by both men and women.  In the first large-scale government survey measuring Americans' sexual orientation, the NHIS reported in July 2014 that only 0.7 percent of Americans identify as bisexual. 
A collection of recent Western surveys finds that about 10% of women and 4% of men identify as mostly heterosexual, 1% of women and 0.5% of men as bisexual, and 0.4% of women and 0.5% of men as mostly homosexual. 
Across cultures, there is some variance in the prevalence of bisexual behavior,  but there is no persuasive evidence that there is much variance in the rate of same-sex attraction.  The World Health Organization estimates a worldwide prevalence of men who have sex with men between 3 and 16%, many of whom have sex with women as well. 
There is no consensus among scientists about the exact reasons that an individual develops a heterosexual, bisexual or homosexual orientation.    Although scientists favor biological models for the cause of sexual orientation,  they do not believe that the development of sexual orientation is the result of any one factor. They generally believe that it is determined by a complex interplay of biological and environmental factors, and is shaped at an early age.    There is considerably more evidence supporting nonsocial, biological causes of sexual orientation than social ones, especially for males.  There is no substantive evidence which suggests parenting or early childhood experiences play a role with regard to sexual orientation.  Scientists do not believe that sexual orientation is a choice.   
The American Psychiatric Association stated: "To date there are no replicated scientific studies supporting any specific biological etiology for homosexuality. Similarly, no specific psychosocial or family dynamic cause for homosexuality has been identified, including histories of childhood sexual abuse."  Research into how sexual orientation may be determined by genetic or other prenatal factors plays a role in political and social debates about homosexuality, and also raises fears about genetic profiling and prenatal testing. 
Magnus Hirschfeld argued that adult sexual orientation can be explained in terms of the bisexual nature of the developing fetus: he believed that in every embryo there is one rudimentary neutral center for attraction to males and another for attraction to females. In most fetuses, the center for attraction to the opposite sex developed while the center for attraction to the same sex regressed, but in fetuses that became homosexual, the reverse occurred. Simon LeVay has criticized Hirschfeld's theory of an early bisexual stage of development, calling it confusing; LeVay maintains that Hirschfeld failed to distinguish between saying that the brain is sexually undifferentiated at an early stage of development and saying that an individual actually experiences sexual attraction to both men and women. According to LeVay, Hirschfeld believed that in most bisexual people the strength of attraction to the same sex was relatively low, and that it was therefore possible to restrain its development in young people, something Hirschfeld supported. 
Hirschfeld created a ten-point scale to measure the strength of sexual desire, with the direction of desire being represented by the letters A (for heterosexuality), B (for homosexuality), and A + B (for bisexuality). On this scale, someone who was A3, B9 would be weakly attracted to the opposite sex and very strongly attracted to the same sex, an A0, B0 would be asexual, and an A10, B10 would be very attracted to both sexes. LeVay compares Hirschfeld's scale to that developed by Kinsey decades later. 
Sigmund Freud, the founder of psychoanalysis, believed that every human being is bisexual in the sense of incorporating general attributes of both sexes. In his view, this was true anatomically and therefore also psychologically, with sexual attraction to both sexes being an aspect of this psychological bisexuality. Freud believed that in the course of sexual development the masculine side of this bisexual disposition would normally become dominant in men and the feminine side in women, but that all adults still have 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. Freud's belief in innate bisexuality was rejected by Sándor Radó in 1940 and, following Radó, by many later psychoanalysts. Radó argued that there is no biological bisexuality in humans.  The psychoanalyst Edmund Bergler argued in Homosexuality: Disease or Way of Life? (1956) that bisexuality does not exist and that all supposed bisexuals are homosexuals. 
Alan P. Bell, Martin S. Weinberg, and Sue Kiefer Hammersmith reported in Sexual Preference (1981) that sexual preference was much less strongly connected with pre-adult sexual feelings among bisexuals than it was among heterosexuals and homosexuals. Based on this and other findings, they suggested that bisexuality is more influenced by social and sexual learning than is exclusive homosexuality.  Letitia Anne Peplau et al. wrote that while Bell et al.'s view that biological factors may be more influential on homosexuality than on bisexuality might seem plausible, it has not been directly tested and appears to conflict with available evidence, such as that concerning prenatal hormone exposure. 
Human bisexuality has mainly been studied alongside homosexuality. Van Wyk and Geist argue that this is a problem for sexuality research because the few studies that have observed bisexuals separately have found that bisexuals are often different from both heterosexuals and homosexuals. Furthermore, bisexuality does not always represent a halfway point between the dichotomy. Research indicates that bisexuality is influenced by biological, cognitive and cultural variables in interaction, and this leads to different types of bisexuality. 
In the current debate around influences on sexual orientation, biological explanations have been questioned by social scientists, particularly by feminists who encourage women to make conscious decisions about their life and sexuality. A difference in attitude between homosexual men and women has also been reported, with men more likely to regard their sexuality as biological, "reflecting the universal male experience in this culture, not the complexities of the lesbian world." There is also evidence that women's sexuality may be more strongly affected by cultural and contextual factors. 
The critic Camille Paglia has promoted bisexuality as an ideal.  Harvard Shakespeare professor Marjorie Garber made an academic case for bisexuality with her 1995 book Vice Versa: Bisexuality and the Eroticism of Everyday Life, in which she argued that most people would be bisexual if not for repression and other factors such as lack of sexual opportunity. 
Brain structure and chromosomes
LeVay's (1991) examination at autopsy of 18 homosexual men, 1 bisexual man, 16 presumably heterosexual men and 6 presumably heterosexual women found that the INAH 3 nucleus of the anterior hypothalamus of homosexual men was smaller than that of heterosexual men and closer in size of heterosexual women. Although grouped with homosexuals, the INAH 3 size of the one bisexual subject was similar to that of the heterosexual men. 
Some evidence supports the concept of biological precursors of bisexual orientation in genetic males. According to Money (1988), genetic males with an extra Y chromosome are more likely to be bisexual, paraphilic and impulsive. 
Some evolutionary psychologists have argued that same-sex attraction does not have adaptive value because it has no association with potential reproductive success. Instead, bisexuality can be due to normal variation in brain plasticity. More recently, it has been suggested that same-sex alliances may have helped males climb the social hierarchy giving access to females and reproductive opportunities. Same-sex allies could have helped females to move to the safer and resource richer center of the group, which increased their chances of raising their offspring successfully. 
Brendan Zietsch of the Queensland Institute of Medical Research proposes the alternative theory that men exhibiting female traits become more attractive to females and are thus more likely to mate, provided the genes involved do not drive them to complete rejection of heterosexuality. 
Also, in a 2008 study, its authors stated that "There is considerable evidence that human sexual orientation is genetically influenced, so it is not known how homosexuality, which tends to lower reproductive success, is maintained in the population at a relatively high frequency." They hypothesized that "while genes predisposing to homosexuality reduce homosexuals' reproductive success, they may confer some advantage in heterosexuals who carry them" and their results suggested that "genes predisposing to homosexuality may confer a mating advantage in heterosexuals, which could help explain the evolution and maintenance of homosexuality in the population." 
In Scientific American Mind, the scientist Emily V. Driscoll stated that homosexual and bisexual behavior is quite common in several species and that it fosters bonding: "The more homosexuality, the more peaceful the species". The article also stated: "Unlike most humans, however, individual animals generally cannot be classified as gay or straight: an animal that engages in a same-sex flirtation or partnership does not necessarily shun heterosexual encounters. Rather, many species seem to have ingrained homosexual tendencies that are a regular part of their society. That is, there are probably no strictly gay critters, just bisexual ones. Animals don't do sexual identity. They just do sex." 
Masculinization of women and hypermasculinization of men has been a central theme in sexual orientation research. There are several studies suggesting that bisexuals have a high degree of masculinization. LaTorre and Wendenberg (1983) found differing personality characteristics for bisexual, heterosexual and homosexual women. Bisexuals were found to have fewer personal insecurities than heterosexuals and homosexuals. This finding defined bisexuals as self-assured and less likely to suffer from mental instabilities. The confidence of a secure identity consistently translated to more masculinity than other subjects. This study did not explore societal norms, prejudices, or the feminization of homosexual males. 
In a research comparison, published in the Journal of the Association for Research in Otolaryngology, women usually have a better hearing sensitivity than males, assumed by researchers as a genetic disposition connected to child bearing. Homosexual and bisexual women have been found to have a hypersensitivity to sound in comparison to heterosexual women, suggesting a genetic disposition to not tolerate high pitched tones. While heterosexual, homosexual and bisexual men have been found to exhibit similar patterns of hearing, there was a notable differential in a sub-group of males identified as hyperfeminized homosexual males who exhibited test results similar to heterosexual women. 
The prenatal hormonal theory of sexual orientation suggests that people who are exposed to excess levels of sex hormones have masculinized brains and show increased homosexuality or bisexuality. Studies providing evidence for the masculinization of the brain have, however, not been conducted to date. Research on special conditions such as congenital adrenal hyperplasia (CAH) and exposure to diethylstilbestrol (DES) indicate that prenatal exposure to, respectively, excess testosterone and estrogens are associated with female–female sex fantasies in adults. Both effects are associated with bisexuality rather than homosexuality. 
There is research evidence that the digit ratio of the length of the 2nd and 4th digits (index finger and ring finger) is somewhat negatively related to prenatal testosterone and positively to estrogen. Studies measuring the fingers found a statistically significant skew in the 2D:4D ratio (long ring finger) towards homosexuality with an even lower ratio in bisexuals. It is suggested that exposure to high prenatal testosterone and low prenatal estrogen concentrations is one cause of homosexuality whereas exposure to very high testosterone levels may be associated with bisexuality. Because testosterone in general is important for sexual differentiation, this view offers an alternative to the suggestion that male homosexuality is genetic. 
The prenatal hormonal theory suggests that a homosexual orientation results from exposure to excessive testosterone causing an over-masculinized brain. This is contradictory to another hypothesis that homosexual preferences may be due to a feminized brain in males. However, it has also been suggested that homosexuality may be due to high prenatal levels of unbound testosterone that results from a lack of receptors at particular brain sites. Therefore, the brain could be feminized while other features, such as the 2D:4D ratio could be over-masculinized. 
Van Wyk and Geist summarized several studies comparing bisexuals with hetero- or homosexuals that have indicated that bisexuals have higher rates of sexual activity, fantasy, or erotic interest. These studies found that male and female bisexuals had more heterosexual fantasy than heterosexuals or homosexuals; that bisexual men had more sexual activities with women than did heterosexual men, and that they masturbated more but had fewer happy marriages than heterosexuals; that bisexual women had more orgasms per week and they described them as stronger than those of hetero- or homosexual women; and that bisexual women became heterosexually active earlier, masturbated and enjoyed masturbation more, and were more experienced in different types of heterosexual contact. 
Research suggests that, for most women, high sex drive is associated with increased sexual attraction to both women and men. For men, however, high sex drive is associated with increased attraction to one sex or the other, but not to both, depending on sexual orientation.  Similarly for most bisexual women, high sex drive is associated with increased sexual attraction to both women and men; while for bisexual men, high sex drive is associated with increased attraction to one sex, and weakened attraction to the other. 
The bisexual community (also known as the bisexual/pansexual, bi/pan/fluid, or non-monosexual community) includes members of the LGBT community who identify as bisexual, pansexual or fluid.  Because some bisexual people do not feel that they fit into either the gay or the heterosexual world, and because they have a tendency to be "invisible" in public, some bisexual persons are committed to forming their own communities, culture, and political movements. Some who identify as bisexual may merge themselves into either homosexual or heterosexual society. Other bisexual people see this merging as enforced rather than voluntary; bisexual people can face exclusion from both homosexual and heterosexual society on coming out. Psychologist Beth Firestein states that bisexuals tend to internalize social tensions related to their choice of partners  and feel pressured to label themselves as homosexuals instead of occupying the difficult middle ground where attraction to people of both sexes would defy society's value on monogamy.  These social tensions and pressure may affect bisexuals' mental health, and specific therapy methods have been developed for bisexuals to address this concern. 
Bisexual behaviors are also associated in popular culture with men who engage in same-sex activity while otherwise presenting as heterosexual. The majority of such men — said to be living on the down-low — do not self-identify as bisexual.  However, this may be a cultural misperception closely related to that of other LGBT individuals who hide their actual orientation due to societal pressures, a phenomenon colloquially called "being closeted".[ original research?]
In the U.S., a 2013 Pew survey showed that 28% of bisexuals said that "all or most of the important people in their life are aware that they are LGBT" vs. 77% of gay men and 71% of lesbians. Furthermore, when broken down by gender, only 12% of bisexual men said that they were "out" vs. 33% of bisexual women. 
Perceptions and discrimination
Like people of other LGBT sexualities, bisexuals often face discrimination. In addition to the discrimination associated with homophobia, bisexuals frequently contend with discrimination from gay men, lesbians, and straight society around the word bisexual and bisexual identity itself.    The belief that everyone is bisexual (especially women as opposed to men),   or that bisexuality does not exist as a unique identity, is common.   This stems from two views: In the heterosexist view, people are presumed to be sexually attracted to the opposite sex, and it is sometimes reasoned that a bisexual person is simply a heterosexual person who is sexually experimenting.  In the monosexist view, it is believed that people cannot be bisexual unless they are equally sexually attracted to both sexes, regulating sexual orientation to being about the sex or gender one prefers.   In this view, people are either exclusively homosexual (gay/lesbian) or exclusively heterosexual (straight),  closeted homosexual people who wish to appear heterosexual,  or heterosexuals who are experimenting with their sexuality.   Assertions that one cannot be bisexual unless equally sexually attracted to both sexes, however, are disputed by various researchers, who have reported bisexuality to fall on a continuum, like sexuality in general.  
Male bisexuality is particularly presumed to be non-existent,  with sexual fluidity studies adding to the debate. In 2005, researchers Gerulf Rieger, Meredith L. Chivers, and J. Michael Bailey used penile plethysmography to measure the arousal of self-identified bisexual men to pornography involving only men and pornography involving only women. Participants were recruited via advertisements in gay-oriented magazines and an alternative paper. They found that the self-identified bisexual men in their sample had genital arousal patterns similar to either homosexual or heterosexual men. The authors concluded that "in terms of behavior and identity, bisexual men clearly exist", but that male bisexuality had not been shown to exist with respect to arousal or attraction.  The assertion of Bailey that "for men arousal is orientation" was criticized by Fairness and Accuracy in Reporting (FAIR) as a simplification which neglects to account for behavior and self-identification.  Further, some researchers hold that the technique used in the study to measure genital arousal is too crude to capture the richness (erotic sensations, affection, admiration) that constitutes sexual attraction.  The National Gay and Lesbian Task Force called the study and The New York Times coverage of it flawed and biphobic. 
The American Institute of Bisexuality stated that Bailey's study was misinterpreted and misreported by both The New York Times and its critics.  In 2011, Bailey and other researchers reported that among men with a history of several romantic and sexual relationships with members of both sexes, high levels of sexual arousal were found in response to both male and female sexual imagery.   The subjects were recruited from a Craigslist group for men seeking intimacy with both members of a heterosexual couple. The authors said that this change in recruitment strategy was an important difference, but it may not have been a representative sample of bisexual-identified men. They concluded that "bisexual-identified men with bisexual arousal patterns do indeed exist", but could not establish whether such a pattern is typical of bisexual-identified men in general.  
Bisexual erasure (or bisexual invisibility) is the tendency to ignore, remove, falsify, or reexplain evidence of bisexuality in culture, history, academia, news media and other primary sources.    In its most extreme form, bisexual erasure includes denying that bisexuality exists.   It is often a manifestation of biphobia,    although it does not necessarily involve overt antagonism.
There is increasing inclusion and visibility of bisexuals, particularly in the LGBT community.   American psychologist Beth Firestone writes that since she wrote her first book on bisexuality, in 1996, "bisexuality has gained visibility, although progress is uneven and awareness of bisexuality is still minimal or absent in many of the more remote regions of our country and internationally." 
A common symbol of the bisexual community is the bisexual pride flag, which has a deep pink stripe at the top for homosexuality, a blue one on the bottom for heterosexuality, and a purple one – blending the pink and blue – in the middle to represent bisexuality. 
Another symbol with a similarly symbolic color scheme is a pair of overlapping pink and blue triangles, forming purple or lavender where they intersect. This design is an expansion on the pink triangle, a well-known symbol for the homosexual community. 
Some bisexual individuals object to the use of a pink triangle, as it was the symbol that Adolf Hitler's regime use to tag and persecute homosexuals. In response, a double crescent moon symbol was devised specifically to avoid the use of triangles.  This symbol is common in Germany and surrounding countries. 
In Steve Lenius' original 2001 paper, he explored the acceptance of bisexuality in a supposedly pansexual BDSM community. The reasoning behind this is that "coming-out" had become primarily the territory of the gay and lesbian, with bisexuals feeling the push to be one or the other (and being right only half the time either way). What he found in 2001, was that people in BDSM were open to discussion about the topic of bisexuality and pansexuality and all controversies they bring to the table, but personal biases and issues stood in the way of actively using such labels. A decade later, Lenius (2011) looked back on his study and considered if anything has changed. He concluded that the standing of bisexuals in the BDSM and kink community was unchanged, and believed that positive shifts in attitude were moderated by society's changing views towards different sexualities and orientations. But Lenius (2011) does emphasize that the pansexual promoting BDSM community helped advance greater acceptance of alternative sexualities.  
Brandy Lin Simula (2012), on the other hand, argues that BDSM actively resists gender conforming and identified three different types of BDSM bisexuality: gender-switching, gender-based styles (taking on a different gendered style depending on gender of partner when playing), and rejection of gender (resisting the idea that gender matters in their play partners). Simula (2012) explains that practitioners of BDSM routinely challenge our concepts of sexuality by pushing the limits on pre-existing ideas of sexual orientation and gender norms. For some, BDSM and kink provides a platform in creating identities that are fluid, ever-changing. 
Feminist positions on bisexuality range greatly, from acceptance of bisexuality as a feminist issue to rejection of bisexuality as reactionary and anti-feminist backlash to lesbian feminism.  A number of women who were at one time involved in lesbian-feminist activism have since come out as bisexual after realizing their attractions to men. A widely studied example of lesbian-bisexual conflict in feminism was the Northampton Pride March during the years between 1989 and 1993, where many feminists involved debated over whether bisexuals should be included and whether or not bisexuality was compatible with feminism.
Common lesbian-feminist critiques leveled at bisexuality were that bisexuality was anti-feminist, that bisexuality was a form of false consciousness, and that bisexual women who pursue relationships with men were "deluded and desperate." Tensions between bisexual feminists and lesbian feminists have eased since the 1990s, as bisexual women have become more accepted in the feminist community,  but some lesbian feminists such as Julie Bindel are still critical of bisexuality. Bindel has described female bisexuality as a "fashionable trend" being promoted due to "sexual hedonism" and broached the question of whether bisexuality even exists.  She has also made tongue-in-cheek comparisons of bisexuals to cat fanciers and devil worshippers.  Sheila Jeffreys writes in The Lesbian Heresy that while many feminists are comfortable working alongside gay men, they are uncomfortable interacting with bisexual men. Jeffreys states that while gay men are unlikely to sexually harass women, bisexual men are just as likely to be bothersome to women as heterosexual men. 
Donna Haraway was the inspiration and genesis for cyberfeminism with her 1985 essay "A Cyborg Manifesto: Science, Technology, and Socialist-Feminism in the Late Twentieth Century" which was reprinted in Simians, Cyborgs and Women: The Reinvention of Nature (1991). Haraway's essay states that the cyborg "has no truck with bisexuality, pre-oedipal symbiosis, unalienated labor, or other seductions to organic wholeness through a final appropriation of all powers of the parts into a higher unity." 
Ancient Greeks and Romans did not associate sexual relations with well-defined labels, as modern Western society does. Men who had male lovers were not identified as homosexual, and may have had wives or other female lovers.
Ancient Greek religious texts, reflecting cultural practices, incorporated bisexual themes. The subtexts varied, from the mystical to the didactic.  Spartans thought that love and erotic relationships between experienced and novice soldiers would solidify combat loyalty and unit cohesion, and encourage heroic tactics as men vied to impress their lovers. Once the younger soldiers reached maturity, the relationship was supposed to become non-sexual, but it is not clear how strictly this was followed. There was some stigma attached to young men who continued their relationships with their mentors into adulthood.  For example, Aristophanes calls them euryprôktoi, meaning "wide arses", and depicts them like women. 
Similarly, in ancient Rome, gender did not determine whether a sexual partner was acceptable, as long as a man's enjoyment did not encroach on another's man integrity. It was socially acceptable for a freeborn Roman man to want sex with both female and male partners, as long as he took the penetrative role.  The morality of the behavior depended on the social standing of the partner, not gender per se. Both women and young men were considered normal objects of desire, but outside marriage a man was supposed to act on his desires only with slaves, prostitutes (who were often slaves), and the infames. It was immoral to have sex with another freeborn man's wife, his marriageable daughter, his underage son, or with the man himself; sexual use of another man's slave was subject to the owner's permission. Lack of self-control, including in managing one's sex life, indicated that a man was incapable of governing others; too much indulgence in "low sensual pleasure" threatened to erode the elite male's identity as a cultured person. 
Alfred Kinsey conducted the first large surveys of homosexual behavior in the United States during the 1940s. The results shocked the readers of his day because they made same-sex behavior and attractions seem so common.  His 1948 work Sexual Behavior in the Human Male stated that among men "nearly half (46%) of the population engages in both heterosexual and homosexual activities, or reacts to persons of both sexes, in the course of their adult lives" and that "37% of the total male population has at least some overt homosexual experience to the point of orgasm since the onset of adolescence."  Kinsey himself disliked the use of the term bisexual to describe individuals who engage in sexual activity with both males and females, preferring to use bisexual in its original, biological sense as hermaphroditic, stating, "Until it is demonstrated [that] taste in a sexual relation is dependent upon the individual containing within his anatomy both male and female structures, or male and female physiological capacities, it is unfortunate to call such individuals bisexual."   Although more recent researchers believe that Kinsey overestimated the rate of same-sex attraction,  :9 :147 his work is considered pioneering and some of the most well known sex research of all time. :29
Bisexuality tends to be associated with negative media portrayals; references are sometimes made to stereotypes or mental disorders. In an article regarding the 2005 film Brokeback Mountain, sex educator Amy Andre argued that in films, bisexuals are often depicted negatively: 
I like movies where bisexuals come out to each other together and fall in love, because these tend to be so few and far between; the most recent example would be 2002's lovely romantic comedy, Kissing Jessica Stein. Most movies with bi characters paint a stereotypical picture.... The bi love interest is usually deceptive ( Mulholland Drive), over-sexed ( Sex Monster), unfaithful ( High Art), and fickle ( Three of Hearts), and might even be a serial killer, like Sharon Stone in Basic Instinct. In other words, the bisexual is always the cause of the conflict in the film.— Amy Andre, American Sexuality Magazine
Using a content analysis of more than 170 articles written between 2001 and 2006, sociologist Richard N. Pitt, Jr. concluded that the media pathologized black bisexual men's behavior while either ignoring or sympathizing with white bisexual men's similar actions. He argued that the black bisexual man is often described as a duplicitous heterosexual man spreading the HIV/AIDS virus. Alternatively, the white bisexual man is often described in pitying language as a victimized homosexual man forced into the closet by the heterosexist society around him. 
In 1914 the first documented appearance of bisexual characters (female and male) in an American motion picture occurred in A Florida Enchantment, by Sidney Drew.  However, under the censorship required by the Hays Code, the word bisexual could not be mentioned, and almost no bisexual characters appeared in American film from 1934 until 1968. 
Notable and varying portrayals of bisexuality can be found in mainstream movies such as Black Swan (2010), Frida (2002), Showgirls (1995), The Pillow Book (1996), Alexander (2004), The Rocky Horror Picture Show (1975), Henry & June (1990), Chasing Amy (1997), Velvet Goldmine (1998), Kissing Jessica Stein (2001), The Fourth Man (1993), Basic Instinct (1992), Mulholland Drive (2001), Sunday Bloody Sunday (1971), Something for Everyone (1970), The Rules of Attraction (2002), Brokeback Mountain (2005), and Call Me by Your Name (2017).
Virginia Woolf's Orlando: A Biography (1928) is an early example of bisexuality in literature. The story, of a man who changes into a woman without a second thought, was based on the life of Woolf's lover Vita Sackville-West. Woolf used the gender switch to avoid the book being banned for homosexual content. The pronouns switch from male to female as Orlando's gender changes. Woolf's lack of definite pronouns allows for ambiguity and lack of emphasis on gender labels.  Her 1925 book Mrs Dalloway focused on a bisexual man and a bisexual woman in sexually unfulfilled heterosexual marriages in later life. Following Sackille-West's death, her son Nigel Nicolson published Portrait of a Marriage, one of her diaries recounting her affair with a woman during her marriage to Harold Nicolson. Other early examples include works of D.H. Lawrence, such as Women in Love (1920), and Colette's Claudine (1900–1903) series.
The main character in Patrick White's novel, The Twyborn Affair (1979), is bisexual. Contemporary novelist Bret Easton Ellis' novels, such as Less Than Zero (1985) and The Rules of Attraction (1987) frequently feature bisexual male characters; this "casual approach" to bisexual characters recurs throughout Ellis' work. 
Rock musician David Bowie famously declared himself bisexual in an interview with Melody Maker in January 1972, a move coinciding with the first shots in his campaign for stardom as Ziggy Stardust.  In a September 1976 interview with Playboy, Bowie said, "It's true—I am a bisexual. But I can't deny that I've used that fact very well. I suppose it's the best thing that ever happened to me."  In a 1983 interview, he said it was "the biggest mistake I ever made",   elaborating in 2002 he explained "I don't think it was a mistake in Europe, but it was a lot tougher in America. I had no problem with people knowing I was bisexual. But I had no inclination to hold any banners or be a representative of any group of people. I knew what I wanted to be, which was a songwriter and a performer [...] America is a very puritanical place, and I think it stood in the way of so much I wanted to do." 
In 1995, Jill Sobule sang about bi-curiosity in her song "I Kissed a Girl", with a video that alternated images of Sobule and a boyfriend along with images of her with a girlfriend. Another song with the same name by Katy Perry also hints at the same theme. Some activists suggest the song merely reinforces the stereotype of bisexuals experimenting and of bisexuality not being a real sexual preference. Lady Gaga has also stated that she is bisexual,  and has acknowledged that her song " Poker Face" is about fantasizing about a woman while being with a man. 
Brian Molko, lead singer of Placebo is openly bisexual.  Green Day frontman Billie Joe Armstrong has also identified himself as bisexual, saying in a 1995 interview with The Advocate, "I think I've always been bisexual. I mean, it's something that I've always been interested in. I think people are born bisexual, and it's just that our parents and society kind of veer us off into this feeling of 'Oh, I can't.' They say it's taboo. It's ingrained in our heads that it's bad, when it's not bad at all. It's a very beautiful thing."  In 2014 Armstrong discussed songs such as "Coming Clean" stating, "It was a song about questioning myself. There are these other feelings you may have about the same sex, the opposite sex, especially being in Berkeley and San Francisco then. People are acting out what they're feeling: gay, bisexual, transgender, whatever. And that opens up something in society that becomes more acceptable. Now we have gay marriage becoming recognized... I think it's a process of discovery. I was willing to try anything." 
In the Netflix original series Orange is the New Black the main character, Piper Chapman, played by actress Taylor Schilling, is a bisexual female inmate who is shown having relationships with both men and women. In season one, before entering the prison, Piper is engaged to male fiancé Larry Bloom, played by actor Jason Biggs. Then, upon entering the prison, she reconnects with former lover (and fellow inmate), Alex Vause, played by Laura Prepon.   Another character who is portrayed as bisexual in the show is an inmate named Lorna Morello, played by actress Yael Stone. She has an intimate relationship with fellow inmate Nicky Nichols, played by Natasha Lyonne, while still yearning for her male “fiance”, Christopher MacLaren, played by Stephen O'Reilly. 
The FOX television series House features a bisexual female doctor, Remy "Thirteen" Hadley, played by Olivia Wilde, from season four onwards. The same network had earlier aired the television series The O.C., which for a time featured bisexual Alex Kelly (also played by Olivia Wilde), the local rebellious hangout spot's manager, as a love interest of Marissa Cooper.  In the HBO drama Oz, Chris Keller was a bisexual serial killer who tortured and raped various men and women. Other films in which bisexual characters conceal murderous neuroses include Black Widow, Blue Velvet, Cruising, Single White Female, and Girl, Interrupted.[ citation needed]
The Showcase supernatural crime drama, Lost Girl, about creatures called Fae who live secretly among humans, features a bisexual protagonist, Bo,  played by Anna Silk. In the story arc she is involved in a love triangle between Dyson, a wolf- shapeshifter (played by Kris Holden-Ried), and Lauren Lewis,  a human doctor (played by Zoie Palmer) in servitude to the leader of the Light Fae clan.
In the BBC TV science fiction show Torchwood, several of the main characters appear to have fluid sexuality. Most prominent among these is Captain Jack Harkness, a pansexual who is the lead character and an otherwise conventional science fiction action hero. Within the logic of the show, where characters can also interact with alien species, producers sometimes use the term "omnisexual" to describe him.  Jack's ex, Captain John Hart is also bisexual.  Of his female exes, significantly at least one ex-wife and at least one woman with whom he has had a child have been indicated. Some critics draw the conclusion that the series more often shows Jack with men than women.  Creator Russell T Davies says one of pitfalls of writing a bisexual character is you "fall into the trap" of "only having them sleep with men." He describes of the show's fourth series, "You'll see the full range of his appetites, in a really properly done way."  The preoccupation with bisexuality has been seen by critics as complementary to other aspects of the show's themes. For heterosexual character Gwen Cooper, for whom Jack harbors romantic feelings, the new experiences she confronts at Torchwood, in the form of "affairs and homosexuality and the threat of death", connote not only the Other but a "missing side" to the Self.  Under the influence of an alien pheromone, Gwen kisses a woman in Episode 2 of the series. In Episode 1, heterosexual Owen Harper kisses a man to escape a fight when he is about to take the man's girlfriend. Quiet Toshiko Sato is in love with Owen, but has also had brief romantic relationships with a female alien and a male human.
In October 2009, "A Rose By Any Other Name"  was released as a " webisode" series on YouTube. Directed by bisexual rights advocate Kyle Schickner,  the plot centers around a lesbian-identified woman who falls in love with a straight man and discovers she is actually bisexual. 
Among other animals
Many non-human animal species exhibit bisexual behavior.    Examples of mammals that display such behavior include the bonobo (formerly known as the pygmy chimpanzee), orca, and the bottlenose dolphin.     Examples of birds include some species of gulls and Humboldt penguins. Other examples of bisexual behavior occur among fish and flatworms. 
Many species of animals are involved in the acts of forming sexual and non-sexual relationship bonds between the same sex; even when offered the opportunity to breed with members of the opposite sex, they pick the same sex. Some of these species are gazelles, antelope, bison, and sage grouse. 
In some cases, animals will choose to engage in sexual activity with different sexes at different times in their lives, and will sometimes engage in sexual activity with different sexes at random. Same-sex sexual activity can also be seasonal in some animals, like male walruses who often engage in same-sex sexual activity with each other outside of the breeding season and will revert to heterosexual sexual activity during breeding season. 
- Bisexual theory
- Bisexual chic
- Bisexual erasure
- Journal of Bisexuality
- List of bisexual characters in literature
- List of bisexual people
- List of gay, lesbian or bisexual people
- List of LGBT characters in television and radio
- List of LGBT-related organizations
- List of media portrayals of bisexuality
- Situational sexual behavior
- "Sexual orientation, homosexuality and bisexuality". American Psychological Association. Archived from the original on 8 August 2013. Retrieved 21 April 2014.
- "Sexual Orientation". American Psychiatric Association. Archived from the original on 26 July 2011. Retrieved 3 December 2012.
- "Understanding Bisexuality". American Psychological Association. 2019. Retrieved 8 March 2019.
- Soble, Alan (2006). "Bisexuality". Sex from Plato to Paglia: a philosophical encyclopedia. 1. Greenwood Publishing Group. p. 115. ISBN 978-0-313-32686-8.
- Carroll JL (2015).
Sexuality Now: Embracing Diversity.
Cengage Learning. p. 322.
Pansexuality is also sometimes included under the definition of bisexuality, since pansexuality rejects the gender binary and encompasses romantic or sexual attractions to all gender identities.
- Rice, Kim (2009). "Pansexuality". In Marshall Cavendish Corporation (ed.).
Sex and Society. 2.
Marshall Cavendish. p. 593.
978-0-7614-7905-5. Retrieved 3 October 2012.
In some contexts, the term pansexuality is used interchangeably with bisexuality, which refers to attraction to individuals of both sexes... Those who identify as bisexual feel that gender, biological sex, and sexual orientation should not be a focal point in potential relationships.
- Rosario, M.; Schrimshaw, E.; Hunter, J.; Braun, L. (2006). "Sexual identity development among lesbian, gay, and bisexual youths: Consistency and change over time". Journal of Sex Research. 43 (1): 46–58. doi: 10.1080/00224490609552298. PMC 3215279. PMID 16817067.
- Frankowski BL; American Academy of Pediatrics Committee on Adolescence (June 2004). "Sexual orientation and adolescents". Pediatrics. 113 (6): 1827–32. doi: 10.1542/peds.113.6.1827. PMID 15173519.
- Lamanna, Mary Ann; Riedmann, Agnes; Stewart, Susan D (2014).
Marriages, Families, and Relationships: Making Choices in a Diverse Society.
Cengage Learning. p. 82.
978-1-305-17689-8. Retrieved 11 February 2016.
The reason some individuals develop a gay sexual identity has not been definitively established – nor do we yet understand the development of heterosexuality. The American Psychological Association (APA) takes the position that a variety of factors impact a person's sexuality. The most recent literature from the APA says that sexual orientation is not a choice that can be changed at will, and that sexual orientation is most likely the result of a complex interaction of environmental, cognitive and biological factors...is shaped at an early age...[and evidence suggests] biological, including genetic or inborn hormonal factors, play a significant role in a person's sexuality (American Psychological Association 2010).
- Gail Wiscarz Stuart (2014).
Principles and Practice of Psychiatric Nursing.
Elsevier Health Sciences. p. 502.
978-0-323-29412-6. Retrieved 11 February 2016.
No conclusive evidence supports any one specific cause of homosexuality; however, most researchers agree that biological and social factors influence the development of sexual orientation.
- Gloria Kersey-Matusiak (2012).
Delivering Culturally Competent Nursing Care.
Springer Publishing Company. p. 169.
978-0-8261-9381-0. Retrieved 10 February 2016.
Most health and mental health organizations do not view sexual orientation as a 'choice.'
- Bailey, J. Michael; Vasey, Paul; Diamond, Lisa; Breedlove, S. Marc; Vilain, Eric; Epprecht, Marc (2016). "Sexual Orientation, Controversy, and Science". Psychological Science in the Public Interest. 17 (2): 45–101. doi: 10.1177/1529100616637616. PMID 27113562.
- LeVay, Simon (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation. Oxford University Press. ISBN 9780199752966.
- Balthazart, Jacques (2012). The Biology of Homosexuality. Oxford University Press. ISBN 9780199838820.
- Crompton, Louis (2003). Homosexuality and Civilization. Cambridge, Massachusetts: Belknap Press. ISBN 978-0-674-01197-7.
- Bagemihl, Bruce (1999). Biological Exuberance: Animal Homosexuality and Natural Diversity. London: Profile Books, Ltd. ISBN 978-1-86197-182-1.
- Roughgarden, Joan (May 2004). Evolution's Rainbow: Diversity, Gender, and Sexuality in Nature and People. Berkeley, CA: University of California Press. ISBN 978-0-520-24073-5.
- Driscoll, Emily V. (July 2008). "Bisexual Species: Unorthodox Sex in the Animal Kingdom". Scientific American.
- Harper, Douglas (November 2001). "Bisexuality". Online Etymology Dictionary. Retrieved 16 February 2007.
"Appropriate Therapeutic Responses to Sexual Orientation" (PDF).
American Psychological Association: 63, 86. Retrieved 15 May 2011.
Sexual orientation identity—not sexual orientation—appears to change via psychotherapy, support groups, and life events.Cite journal requires
- Firestein, Beth A. (2007). Becoming Visible: Counseling Bisexuals Across the Lifespan. Columbia University Press. pp. 9–12. ISBN 978-0231137249. Retrieved 3 October 2012.
- Walton, Michael T.; Lykins, Amy D.; Bhullar, Navjot (8 June 2016). "Beyond Heterosexual, Bisexual, and Homosexual: A Diversity in Sexual Identity Expression". Archives of Sexual Behavior. 45 (7): 1591–1597. doi: 10.1007/s10508-016-0778-3. ISSN 0004-0002.
- Flanders, Corey E. (2 January 2017). "Under the Bisexual Umbrella: Diversity of Identity and Experience". Journal of Bisexuality. 17 (1): 1–6. doi: 10.1080/15299716.2017.1297145. ISSN 1529-9716.
- Eisner, Shiri (2013). Bi: Notes for a Bi Revolution. Seal Press. ISBN 978-1-58005-474-4.
- Diamond, Lisa M. (2008). "Female bisexuality from adolescence to adulthood: results from a 10-year longitudinal study". Developmental Psychology. 44 (1): 5–14. doi: 10.1037/0012-16184.108.40.206. PMID 18194000.
- Denizet-Lewis, Benoit (20 March 2014). "The Scientific Quest to Prove Bisexuality Exists". The New York Times Magazine, 20 March 2014. New York Times. Retrieved 21 March 2014.
- "2014 Sexuality Preconference". Fifteenth Annual Meeting of the Society for Personality and Social Psychology - Preconferences. Society for Personality and Social Psychology. Archived from the original on 21 March 2014. Retrieved 21 March 2014.
- Young-Bruehl, Elisabeth (2001). "Are Human Beings "By Nature" Bisexual?". Studies in Gender and Sexuality. 3 (2): 179–213. doi: 10.1080/15240650209349175.
- Kinseys hetero homo rating scale Archived 17 August 2011 at the Wayback Machine Retrieved 7 April 2011.
- Szymanski, Mike (2008). "Moving Closer to the Middle: Kinsey the Movie, and Its Rocky Road to Bisexual Acceptance". Journal of Bisexuality. 8 (3–4): 287–308. doi: 10.1080/15299710802501918.
- Weinberg, Martin S.; Williams, Colin J.; Pryor, Douglas W. (1995). Dual Attraction: Understanding Bisexuality. New York: Oxford University Press. p. 41. ISBN 978-0-19-509841-9.
- McKnight, Jim. Straight Science: Homosexuality, Evolution and Adaptation. Routledge, 1997, p. 33.
- "Frequently Asked Sexuality Questions to the Kinsey Institute". The Kinsey Institute. Retrieved 16 February 2007.
- "Sexual Behavior and Selected Health Measures: Men and Women 15-44 Years of Age, United States, 2002." Mosher et al. U.S. Department of Health and Human Services.
- Carey, Benedict (5 July 2005). "Straight, Gay or Lying? Bisexuality Revisited". The New York Times. Retrieved 24 February 2007.
- Leonard Sax. "Why Are So Many Girls Lesbian or Bisexual?". Sussex Directories/ Psychology Today. Retrieved 28 April 2011.
- Elizabeth Landau (23 August 2011).
"Bisexual men: Science says they're real". CNN. Retrieved 15 August 2011.
...confirms that men with bisexual arousal patterns and bisexual identity definitely exist...
- "Health survey gives government its first large-scale data on gay, bisexual population". Washington Post. Retrieved 20 March 2015.
- Van Wyk PH, Geist CS (1995). "Biology of Bisexuality: Critique and Observations". Journal of Homosexuality. 28 (3–4): 357–373. doi: 10.1300/J082v28n03_11. ISBN 9781317764519. PMID 7560936.
- Between Men: HIV/STI Prevention For Men Who Have Sex With Men, International HIV/AIDS Alliance.
- "Submission to the Church of England's Listening Exercise on Human Sexuality". The Royal College of Psychiatrists. Retrieved 13 June 2013.
- American Psychiatric Association (May 2000). "Gay, Lesbian and Bisexual Issues". Association of Gay and Lesbian Psychiatrics. Archived from the original on 3 January 2009.
- Mitchum, Robert (12 August 2007). "Study of gay brothers may find clues about sexuality". Chicago Tribune. Retrieved 4 May 2007.
- LeVay, Simon (1996). Queer Science: The Use and Abuse of Research into Homosexuality. Cambridge, Massachusetts: The MIT Press. pp. 18–20. ISBN 978-0-262-12199-6.
- LeVay, Simon (1996). Queer Science: The Use and Abuse of Research into Homosexuality. Cambridge, Massachusetts: The MIT Press. p. 22. ISBN 978-0-262-12199-6.
- Ruse, Michael (1988). Homosexuality: A Philosophical Inquiry. Oxford: Basil Blackwell. pp. 22, 25, 45, 46. ISBN 0-631-15275-X.
- Bergler, Edmund (1957). Homosexuality: Disease or Way of Life?. New York: Hill and Wang, Inc. p. 8.
- Bell, Alan P.; Weinberg, Martin S.; Hammersmith, Sue Kiefer (1981). Sexual Preference: Its Development in Men and Women. Bloomington: Indiana University Press. pp. 200–201. ISBN 978-0-253-16673-9.
- Peplau, Letitia Anne; Spalding, Leah R.; Conley, Terri D.; Veniegas, Rosemary C. (1999). "The Development of Sexual Orientation in Women" (PDF). Archived from the original (PDF) on 5 March 2016. Retrieved 11 July 2017.
- Veniegas, Rosemary c.; Terri D. Conley (2000). "Biological Research on Women's Sexual Orientations: Evaluating the Scientific Evidence". Journal of Social Issues. 56 (2): 267–282. doi: 10.1111/0022-4537.00165.
- Paglia, Camille (1995). Vamps and Tramps: New Essays. New York: Penguin Books. p. 94. ISBN 978-0-14-024828-9.
- Garber, Marjorie B. (2000). Bisexuality and the Eroticism of Everyday Life. New York: Routledge. p. 249. ISBN 978-0-415-92661-4.
- Lippa, Richard A. (23 March 2007). "The Relation Between Sex Drive and Sexual Attraction to Men and Women: A Cross-National Study of Heterosexual, Bisexual, and Homosexual Men and Women". Archives of Sexual Behavior. 36 (2): 209–222. doi: 10.1007/s10508-006-9146-z. PMID 17380375.
- "The evolution of homosexuality: Gender bending - The Economist". The Economist. Retrieved 20 March 2015.
- Zietsch, B.; Morley, K.; Shekar, S.; Verweij, K.; Keller, M.; Macgregor, S.; et al. (2008). "Genetic factors predisposing to homosexuality may increase mating success in heterosexuals". Evolution and Human Behavior. 29 (6): 424–433. doi: 10.1016/j.evolhumbehav.2008.07.002.
- "Bisexual Species: Unorthodox Sex in the Animal Kingdom". Archived from the original on 25 January 2010.
- McFadden, D.; Champlin, CA (March 2000). "Comparison of auditory evoked potentials in heterosexual, homosexual, and bisexual males and females". JARO – Journal of the Association for Research in Otolaryngology. 1 (1): 89–99. doi: 10.1007/s101620010008. PMC 2504562. PMID 11548240.
- Robinson, S; Manning, J. T (2000). "The ratio of 2nd to 4th digit length and male homosexuality". Evolution and Human Behavior. 21 (5): 333–345. doi: 10.1016/S1090-5138(00)00052-0. PMID 11053694.
- Lippa, R. A. (2006). "Is High Sex Drive Associated With Increased Sexual Attraction to Both Sexes?. It Depends on Whether You Are Male or Female". Psychological Science. 17 (1): 46–52. doi: 10.1111/j.1467-9280.2005.01663.x. PMID 16371143.
- Estraven (20 April 2009). "We are all somewhere between straight and gay". BiNet USA News and Opinions. Retrieved 24 March 2011.
- DeAngelis, Tori (February 2002). "A new generation of issues for LGBT clients". Monitor on Psychology. American Psychological Association. Retrieved 16 February 2007.
- Boykin, Keith (3 February 2005). "10 Things You Should Know About the DL". Archived from the original on 27 April 2006. Retrieved 23 February 2007.
- Pew Research Center (13 June 2013). "A Survey of LGBT Americans: Attitudes, Experiences and Values in Changing Times" (PDF). pp. 44–45. Archived from the original (PDF) on 14 August 2015. Retrieved 22 July 2015.
- Mary Zeiss Stange; Carol K. Oyster; Jane E. Sloan (2011). Encyclopedia of Women in Today's World. Sage Pubns. pp. 158–161. ISBN 978-1-4129-7685-5. Retrieved 23 June 2012.
- Dworkin, SH (2001). "Treating the bisexual client". Journal of Clinical Psychology. 57 (5): 671–80. doi: 10.1002/jclp.1036. PMID 11304706.
- Yoshino, Kenji (January 2000). "The Epistemic Contract of Bisexual Erasure" (PDF). Stanford Law Review. 52 (2): 353–461. doi: 10.2307/1229482. JSTOR 1229482.
- Merl Storr (2013). Bisexuality: A Critical Reader. Routledge. pp. 104–106. ISBN 978-1134706907. Retrieved 12 September 2015.
- Eisner, Shiri (2013). Bi: Notes for a Bisexual Revolution. Seal Press. p. 71. ISBN 978-1580054751. Retrieved 12 September 2015.
- Donald E. Hall; Maria Pramaggiore (1996). Representing Bisexualities: Subjects and Cultures of Fluid Desire. NYU Press. p. 19. ISBN 978-0814766347. Retrieved 12 September 2015.
- Michael Musto, 7 April 2009. Ever Meet a Real Bisexual? Archived 13 April 2010 at the Wayback Machine, The Village Voice
- Geen, Jessica (28 October 2009). "Bisexual workers 'excluded by lesbian and gay colleagues'". pinknews.co.uk. Retrieved 26 March 2011.
- Rieger G, Chivers ML, Bailey JM (2005). "Sexual arousal patterns of bisexual men". Psychological Science: APS. 16 (8): 579–84. CiteSeerX 10.1.1.502.8782. doi: 10.1111/j.1467-9280.2005.01578.x. PMID 16102058.
- "New York Times Suggests Bisexuals Are 'Lying.' Paper fails to disclose study author's controversial history". Fairness and Accuracy in Reporting. 8 July 2005. Retrieved 22 June 2013.
- National Gay and Lesbian Task Force (July 2005). "The Problems with "Gay, Straight, or Lying?"" (PDF). Archived from the original (PDF) on 16 October 2013. Retrieved 24 July 2006.
- "Controversy over Professor J. Michael Bailey and the Existence of Bisexuality" (PDF). American Institute of Bisexuality. 2012. Archived from the original (PDF) on 20 October 2013. Retrieved 15 March 2015.
- Lehmiller, J. J. (2012). "Are Bisexual People Equally Aroused By Both Sexes?". Sex and Psychology. Retrieved 15 March 2015.
- Rosenthal, AM; Sylva, D; Safron, A; Bailey, JM (2011). "Sexual arousal patterns of bisexual men revisited" (PDF). Biological Psychology. 88 (1): 112–115. doi: 10.1016/j.biopsycho.2011.06.015. PMID 21763395. Retrieved 6 November 2012.
- Rosenthal, A. M; Sylva, David; Safron, Adam; Bailey, J. Michael (2011). "The Male Bisexuality Debate Revisited: Some Bisexual Men Have Bisexual Arousal Patterns". Archives of Sexual Behavior. 41 (1): 135–47. doi: 10.1007/s10508-011-9881-7. PMID 22194088.
- Hutchins, Loraine. "Sexual Prejudice - The erasure of bisexuals in academia and the media". American Sexuality Magazine. San Francisco, CA 94103, United States: National Sexuality Resource Center, San Francisco State University. Archived from the original on 16 December 2007. Retrieved 19 July 2007.CS1 maint: location ( link)
- "Queers United". Archived from the original on 10 February 2013. Retrieved 2 September 2015.
- "Task Force Report On Bisexuality". Archived from the original on 16 February 2014.
- Firestein, Beth A. (2007). Becoming Visible: Counselling Bisexuals Across the Lifespan. Columbia University Press. pp. xvii. ISBN 978-0231137249.
- Page, Michael.
"Bi Pride Flag". Archived from
the original on 29 January 2007. Retrieved 16 February 2007.
The pink color represents sexual attraction to the same sex only, homosexuality, the blue represents sexual attraction to the opposite sex only, heterosexuality, and the resultant overlap color purple represents sexual attraction to both sexes (bi).
- "Symbols of the Gay, Lesbian, Bisexual, and Transgender Movements". 26 December 2004. Archived from the original on 4 December 2004. Retrieved 27 February 2007.
- Koymasky, Matt; Koymasky Andrej (14 August 2006). "Gay Symbols: Other Miscellaneous Symbols". Retrieved 18 February 2007.
- Lenius, S (2001). "Bisexuals and BDSM". Journal of Bisexuality. 1 (4): 69–78. doi: 10.1300/j159v01n04_06.
- Lenius, S (2011). "A Reflection on "Bisexuals and BDSM: Bisexual People in a Pansexual Community"—Ten Years Later (and a Preview of the Next Sexual Revolution)". Journal of Bisexuality. 11 (4): 420–425. doi: 10.1080/15299716.2011.620466.
- Simula, B. L. (2012). "Does Bisexuality 'Undo' Gender? Gender, Sexuality, and Bisexual Behavior Among BDSM Participants". Journal of Bisexuality. 12 (4): 484–506. doi: 10.1080/15299716.2012.729430.
- Wilkinson, Sue (1996). "Bisexuality as Backlash". In Harne, Lynne (ed.). All the Rage: Reasserting Radical Lesbian Feminism. Elaine Miller. New York City: Teacher's College Press. pp. 75–89. ISBN 978-0-807-76285-1. OCLC 35202923.
- Gerstner, David A. (2006). Routledge International Encyclopedia of Queer Culture. United Kingdom: Routledge. pp. 82–3. ISBN 978-0-415-30651-5. Retrieved 3 October 2012.
- Bindel, Julie (12 June 2012). "Where's the Politics in Sex?". The Huffington Post. Retrieved 3 October 2012.
- Bindel, Julie (8 November 2008). "It's not me. It's you". The Guardian. London. Retrieved 3 October 2012.
- Jeffreys, Sheila (1993). The Lesbian Heresy. Melbourne, Australia: Spinifex Press Pty Ltf. p. 124. ISBN 978-1-875559-17-6. Retrieved 4 October 2012.
- "Donna Haraway - A Cyborg Manifesto". Egs.edu. Archived from the original on 22 September 2013. Retrieved 15 September 2015.
- "Common Lives/Lesbian Lives Records, Iowa Women's Archives, University of Iowa Libraries, Iowa City, Iowa". Sdrc.lib.uiowa.edu. Archived from the original on 21 August 2015. Retrieved 3 December 2013.
- van Dolen, Hein. "Greek Homosexuality". Retrieved 17 February 2007.
- Amy Richlin, The Garden of Priapus: Sexuality and Aggression in Roman Humor (Oxford University Press, 1983, 1992), p. 225.
- Catharine Edwards, "Unspeakable Professions: Public Performance and Prostitution in Ancient Rome," in Roman Sexualities, pp. 67–68.
- Kinsey, Alfred C.; Pomeroy, Wardell B.; Martin, Clyde E. (1948). Sexual Behavior in the Human Male. Philadelphia and London: W. B. Saunders Company. pp. 650, 656, 657.
- Lehmiller, Justin (2018). The Psychology of Human Sexuality (Second ed.). John Wiley & Sons Ltd. ISBN 9781119164739.
- Andre, Amy (16 December 2005). "Opinion: Bisexual Cowboys in Love". National Sexuality Resource Center. Archived from the original on 10 February 2009. Retrieved 22 November 2006.
- Pitt Jr., Richard N. (2006). "Downlow Mountain? De/Stigmatizing Bisexuality Through Pitying And Pejorative Discourses In Media". The Journal of Men's Studies. 14 (2): 254–258. doi: 10.1177/106082650601400203. Archived from the original on 30 December 2016.
- Silverman, Stephen M. (9 July 2003). "Angelina Jolie Airs Colorful Past on TV". People. Retrieved 7 April 2015.
- ">> arts >> Bisexuality in Film". glbtq. Archived from the original on 15 October 2012. Retrieved 2012-11-06.
- Livia, Anna (2000). Pronoun Envy: Literary Uses of Linguistic Gender. Oxford University Press, ISBN 9780195138535
- Gordinier, Jeff (June 2010). "Bret Easton Ellis: Eternal Bad Boy". Details. Retrieved 15 June 2010.
- Carr, Roy; Murray, Charles Shaar (1981). Bowie: An Illustrated Record. New York: Avon. ISBN 0-380-77966-8.
- "Interview: David Bowie". Playboy. September 1976. Archived from the original on 1 August 2010. Retrieved 14 September 2010.
- Buckley (2000): p. 401
- Buckley (2005): p. 106
- Collis, Clark (August 2002). "Dear Superstar: David Bowie". blender.com. Alpha Media Group Inc. Archived from the original on 10 May 2008. Retrieved 16 September 2010.
- "Freddie Mercury". Biography.com. Retrieved 23 November 2017.
- "Lady Gaga Rolling Stone Interview".
- "Lady Gaga admits bisexuality and explains "Poker Face" to Barbra Walters". Archived from the original on 17 February 2010.
- Dave West (9 April 2006). "Molko: I wish I kept quiet on sexuality". Digital Spy. Retrieved 20 September 2011.
- "AOL Radio – Listen to Free Online Radio – Free Internet Radio Stations and Music Playlists". Spinner.com. Retrieved 25 November 2013.
- "'Dookie' at 20: Billie Joe Armstrong on Green Day's Punk Blockbuster". Rolling Stone. Archived from the original on 17 July 2014. Retrieved 18 March 2015.
- Cruz, Eliel. "Bisexuality in the Media: Where Are the Bisexuals on TV?" Bisexual.org. Journal of Bisexuality, 1 Sept. 2014. Web. 17 Oct. 2016.
- Zeilinger, Julie. "5 Myths 'Orange Is the New Black' Has Accidentally Dispelled About Bisexuality." Mic Network Inc., 12 June 2015. Web. 17 Oct. 2016.
- ["Games". Writer: Eli Attie; Director: Deran Sarafian. House. Fox. No. 9, season 4.]
- "Real World DC".
- "Emily Schromm talks".
- "Mike Manning Metro Weekly".
- drsquid (30 September 2010).
"Nine Questions with Lost Girl Creator and Writer Michelle Lovretta". RGB Filter. Archived from
the original on 13 May 2013. Retrieved 17 August 2013.
Bo is a succubus, a grown woman, and bisexual....
- ""Lost Girl" showcases the Lauren and Bo relationship for Season 2". AfterEllen. 28 October 2011. Retrieved 28 October 2011.
- Ryan, Maureen (14 July 2007). "Spike from 'Buffy' and 'Torchwood's Captain Jack Harkness — Yowza!". Chicago Tribune. Retrieved 2 June 2009.
- "James Marsters Interview (January 2008)". Radio Times. Archived from the original on 20 January 2008. Retrieved 25 January 2008.
- Davis, Glyn; Needham, Gary (2009). Queer TV. Routledge (28 January 2009). pp. 153–156. ISBN 978-0-415-45046-1.
- Knight, Dominic (8 August 2010). "More Torchwood details revealed". Associated Television Network. Archived from the original on 14 April 2011. Retrieved 8 August 2010.
- Frankel, Valerie Estelle (2010). "Gwen's Evil Stepmother: Concerning Gloves and Magic Slippers". In Andrew Ireland (ed.). Illuminating Torchwood: Essays on Narrative, Character and Sexuality in the BBC Series. McFarland. pp. 90–101. ISBN 9780786455607.
- "Rose By Any Other Name".
- "Fencesitter Films". Archived from the original on 4 September 2009. Retrieved 30 April 2019.
- "From Out Bi Director Kyle Schickner".
- Diamond, Milton (1998). "Bisexuality: A Biological Perspective". Bisexualities – The Ideology and Practice of Sexual Contact with both Men and Women. Archived from the original on 1 January 2007. Retrieved 17 February 2007.
- Scott Bidstrup (2000). "The Natural Crime Against Nature". Retrieved 26 June 2007.
Ancient Greece and Rome
- Eva Cantarella. Bisexuality in the Ancient World, Yale University Press, New Haven, 1992, 2002. ISBN 978-0-300-09302-5
- Kenneth J. Dover. Greek Homosexuality, New York; Vintage Books, 1978. ISBN 0-394-74224-9
- Thomas K. Hubbard. Homosexuality in Greece and Rome, U. of California Press, 2003. ISBN 0-520-23430-8
- Harald Patzer. Die Griechische Knabenliebe [Greek Pederasty], Wiesbaden: Franz Steiner Verlag, 1982. In: Sitzungsberichte der Wissenschaftlichen Gesellschaft an der Johann Wolfgang Goethe-Universität Frankfurt am Main, Vol. 19 No. 1.
- W. A. Percy III. Pederasty and Pedagogy in Archaic Greece, University of Illinois Press, 1996. ISBN 0-252-02209-2
- Stephen O. Murray and Will Roscoe, et al. Islamic Homosexualities: Culture, History, and Literature, New York: New York University Press, 1997. ISBN 0-8147-7468-7
- J. Wright & Everett Rowson. Homoeroticism in Classical Arabic Literature. 1998. ISBN 0-231-10507-X (pbbk)/ ISBN 0-231-10506-1 (hdbk)
- Gary Leupp. Male Colors: The Construction of Homosexuality in Tokugawa Japan, Berkeley, University of California Press, 1995. ISBN 0-520-20900-1
- Tsuneo Watanabe & Jun'ichi Iwata. The Love of the Samurai. A Thousand Years of Japanese Homosexuality, London: GMP Publishers, 1987. ISBN 0-85449-115-5
- Bisexuality: Theories, Research, and Recommendations for the Invisible Sexuality by D. Joye Swan and Shani Habibi, Editors ISBN 9783319715346
- Dual Attraction: Understanding Bisexuality by Martin S. Weinberg, Colin J. Williams, & Douglas W. Pryor, ISBN 0195098412
- Bi Any Other Name : Bisexual People Speak Out by Loraine Hutchins, Editor & Lani Ka'ahumanu, Editor ISBN 1-55583-174-5
- Getting Bi : Voices of Bisexuals Around the World by Robyn Ochs, Editor & Sarah Rowley, Editor ISBN 0-9653881-4-X
- The Bisexual Option by Fritz Klein, MD ISBN 1-56023-033-9
- Bi Men : Coming Out Every Which Way by Ron Suresha and Pete Chvany, Editors ISBN 978-1-56023-615-3
- Bi America : Myths, Truths, And Struggles of an Invisible Community by William E. Burleson ISBN 978-1-56023-478-4
- Bisexuality in the United States : A Social Science Reader by Paula C. Rodriguez Rust, Editor ISBN 0-231-10226-7
- Bisexuality : The Psychology and Politics of an Invisible Minority by Beth A. Firestein, Editor ISBN 0-8039-7274-1
- Current Research on Bisexuality by Ronald C. Fox PhD, Editor ISBN 978-1-56023-289-6
- Bryant, Wayne M.. Bisexual Characters in Film: From Anais to Zee. Haworth Gay & Lesbian Studies, 1997. ISBN 1-56023-894-1
- Moreno-Domínguez, Silvia; Raposo, Tania; Elipe, Paz (2019). "Body Image and Sexual Dissatisfaction: Differences Among Heterosexual, Bisexual, and Lesbian Women". Frontiers in Psychology. doi: 10.3389/fpsyg.2019.00903. ISSN 1664-1078.
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