People with predominantly non-heterosexual orientations have traditionally comprised about 5% of survey respondents in Western countries [1]. Historical and cross-cultural evidence from three separate studies spanning four decades suggests that if a sufficient number of people exist in a society, subcultures populated by same-sex attracted individuals will appear within it, however, non-heterosexual orientation is incredibly difficult to measure for a variety of reasons [1,15,16,17].

Firstly, sexual orientation is not always monolithic in its label. Even with an expanding acronym and vocabulary associated with various queer identities, there is still no foolproof method of measurement for something as intricate as sexuality. Secondly, the different phenomena associated with homosexuality and bisexuality, for example, vary greatly in frequency among studies [1]. Thirdly, these phenomena vary over a person’s lifetime and are subject to change. Thus, measures of population are subject to great variance depending on whether they are based on an individual current pattern of behavior and attraction versus the entirety of these patterns throughout a lifetime [1].

Fourth, arguably the most troublesome difficulty in the research on sexual demographics is that not everyone who is non-heterosexual will disclose their sexual identity. Fear of repercussions, however much anonymity is guaranteed by researchers, may distort results, and more importantly there is also an element of genuine uncertainty people experience when looking for the most accurate ways to label their sexualities.

Women are more likely to report a bisexual orientation than an exclusively same-sex orientation and men show the opposite pattern [1]. In regards to the measurement of sexual orientation, men’s has been closely linked to their pattern of sexual arousal to various stimuli, while women’s sexual orientation cannot be consistently measured this way [1]. Women are also different from men in that they are more likely to experience same-sex attraction in the context of a close affectionate relationship or friendship, and women’s sexual orientation is also subject to a higher likelihood of change over time [1]. What are some of the proposed explanations for this gendered difference? One possibility is cultural differences. Our culture consistently produces depictions of female beauty that are sexualized and it may be assumed that exposure to these images from an early age sensitizes both men and women to experience sexual arousal towards an idealized female body [1].

Recently, the research organization Gallup (2021) released new findings about the percentage of American adults who identify as LGBTQ+. Since the last substantial survey of its kind in 2017, the percentage of rainbow-identified adults in the United States has risen over 1% to a total of 5.6% [52]. Gallup explains that a large portion of this increase is a product of the saturation of non-heterosexual adults within the Gen Z population. More than 1 in 5 of these young adults, age 18 to 23, identify as LGBTQ and 72% of those who do identify as bisexual [52]. There is every reason to think this trend will continue. Sexual identity is an intricate combination of biological and social factors. As our society further integrates ideas of fluidity within gender identity and sexual orientation, opportunity grows for individuals to identify with non-binary gender and sexual identities beyond the reductive categories of heterosexual and homosexual.

Young people, who today have access to the internet and other social media platforms that connect them with like-minded peers and information sources, utilize a larger toolbox of language to identify their experience and selves than previous generations. It is important to distinguish between sexual attraction, sexual behavior, and sexual identity, each of which are distinct but heavily overlapping elements that make up a person’s sexuality, as each have their own developmental paths. This will be discussed further below, but for example, a person may be predominantly attracted to the other sex, but exhibit mostly same-sex sexual behavior. This may be due to external factors, which put people in exclusively homosocial environments such as prison or a single-sex school, or it may come as a way of expressing and concretizing bonds of friendships. Meanwhile, both behavior and attraction have been shown to be surprisingly independent from sexual identity; for some people, their conception of what it means to be a “heterosexual” might not be primarily connected to the sex of the people they sleep with, or even whom they fantasize about while masturbating. Sexual identity is formed by an informational exchange between sexual actions and desires and cultural time and space in which they exist.

Gallup’s study reported that 7.6% of American adults chose not to select any sexual orientation or identity. This might be explained in part by a hesitancy to claim a sexual orientation due to personal confusion or vacillation, or else by a frustration with the demand to label oneself. The 7.6% of non-identifiers may also envelop the growing number of people identifying as asexual and/or aromantic, and perhaps may even be related to the high percentage of LGBTQ+ Americans identifying as bisexual (54.6%) [52]. Of course, bisexuality is widely considered a specific category of sexual orientation; it is, after all, the third letter in the often used LGBTQ+ acronym. However, bisexuality, pansexuality, and queer are also signifiers of both the non-categorizable nature of sexual attraction as well as the growing understanding of sexuality as fluid and changeable over time.

We explore this fluidity as it relates to sexual identity, attraction, and behavior and consider the various shades of bisexuality as it relates to the level of free will that is intrinsic in any person’s sexual identity. When a person’s emotional experience is suspended between different types of attractions, social settings, friendships, and understandings of others (just to name a few variables), free will takes over and the choices people make based on the various fluctuating pieces of themselves contribute to their complex and individual sense of identity.

The “etiology” (the study of causes and origins) of sexual orientation has been integral to the politics and ethics of non-normative sexuality perhaps since Richard Freiherr von Krafft-Ebing published his Psychopathia Sexualis in 1886, developing a theory that explains what makes a person attracted to the same sex [62]. Since then, the debate over the dignity of LGB people, the rationality of their socio-political persecution, and their right to same-sex sexual intimacy has largely pivoted around the causation of homosexuality.  

Positing that homosexual orientations are inborn traits and the strict result of genetics has been at the core of gay political mobilization. The rise of gay liberation in the 1970s was quickly followed by social conservative reaction: groups like The Moral Majority argued that homosexuality could be instilled into people, particularly at a young age, via exposure to the “homosexual lifestyle” and other un-Christian influences. Some fringe clinicians began developing techniques for “conversion therapy” designed to alter sexual desires. This movement was fostered by organizations such as NARTH (National Association for Research & Therapy of Homosexuality) and has been widely criticized on both ethical and effectual grounds. Many states now outlaw it.

Now that homosexuality has for 50 years no longer been classified as a mental illness in the American Psychiatric Association’s key publications and has gained unprecedented public acceptance, a level of critical distance in the science of sexual orientation can do a great service in advancing our understand of the great mystery of human sexuality. Considering the number of studies, data, and anecdotes available to help answer the question of sexual orientation, we will summarize the current understanding of the matter with a statement from the American Psychological Association.

“Although much research has examined the possible genetic, hormonal, developmental, social and cultural influences on sexual orientation, no findings have emerged that permit scientists to conclude that sexual orientation is determined by any particular factor or factors” [2].

That being said, there still exists plenty of evidence to support many interactive factors within us that play a role in the formation and self-realization of our sexual attractions and behaviors.

As Patrick R. Grzanka, the Director of the Social Action Research Team, stated, “If you know anything about social constructionism, then you know that [currently recognized] sexual categories are very recent. How then could they be rooted in our genome?” [2] Grzanka’s words provide a constructive framework for sexuality research in that there is always more to understand: how we know and experience ourselves and the world around us is constantly changing.

Political attitudes about sexual orientation often correlate with views of the causes of sexual orientation [2]. Most of the scientific research attempting to explain sexual orientation has used self-reported non-heterosexual subjects. Part of the reality of identity politics is that certain people engage in “homosexual behavior” but do not identify as gay. The same complication is present in individuals who experience same-sex attraction, but do not engage in same-sex behavior. Terms for sexual orientation are labels and labels carry baggage; the word “gay,” for instance, often conjures images beyond simply same-sex attractions and behaviors, but also rainbows, glitter, parades, as well as gender nonconformity, bohemianism, and particular positions on religious and social issues. The ephemeral and inscrutable nature of sexuality alone makes consistent data on the distribution of sexual orientation difficult; the variety of cultural meanings attached to queer desires muddy the water even more.    

The Kinsey scale, first published in Sexual Behavior in the Human Male in 1948, was developed by Drs. Alfred Kinsey, Wardell Pomeroy, and Clyde Martin [18]. After interviewing thousands of people about their sexual histories and feelings, their research showed that sexual identity, attraction, and behavior were not consistent across time. This led Kinsey and his associates to use a seven-point scale instead of assigning people to the three categories of heterosexual, bisexual, and homosexual [18]. Participants would rate their sexuality on a scale of 0 to 6, 0 indicating entirely heterosexual and 6 entirely homosexual. The additional category of ‘X’ was for individuals with no socio-sexual contacts or reactions.

Kinsey and his associates established a more flexible understanding of sexuality, which can be usefully applied when talking with your children, especially if they approach you with questions about their non-normative sexualities and gender identities. Kids with these experiences will also often want an explanation for why they feel the way that they do, and this can be a great opportunity to explore the many factors influencing sex and gender diversity.

A single explanation for differences in sexual orientation cannot determine all three of the main components of someone’s sexuality: sexual identity, sexual attraction, and sexual behavior. The similarities, differences, and interactions between these three components of an individual’s sexuality combine to create the different sexual narratives of ourselves we use throughout our lifetimes.

Too often media coverage of how many people are LGBTQ fails to distinguish between the three parameters of sexual attraction, behavior, and identity. Those who feel sexual attraction to someone of the same sex or are curious about it do not always act upon it behaviorally, and even those who act upon it do not necessarily consider it part of their identity such that they would respond to a pollster that they are “gay.” Conversely, a minor may come out to you as “gay” when they have no actual behavioral experience of a same-sex relationship. Some call themselves “queer” even though their attractions and experiences are all opposite-sex, because they see the term as a political statement that their sexuality is different from the norm or that they identify with friends who are LGBT. It is therefore important to have a clear understanding of the differences between attraction, behavior, and identity, as well as the differences between L, G, B, T, and Q.

1. Sexual identity

Sexual identity is easily distinguished from sexual behavior, but sexual identity and sexual attraction, other times referred to as sexual preference, are more theoretically intertwined. “Sexual orientation” is used to encompass both the sexual and romantic attractions a person has [1,2]. The following two phenomena (sexual attraction and sexual behavior) are encompassed within one’s sexual orientation; yet, the three entities function independently from each other as well. Sexual orientation is sometimes also referred to as “sexual identity,” which is one’s self-conception as homosexual, bisexual, queer, etc. It is important to note that they are not the same thing, although sexual orientation often influences one’s sexual identity.

Sexual identity is asserted by an individual and is not easily measured with science or biology. Sexual identity relates to sexual attraction and behavior within various social and biological contexts. Unlike sexual attraction and behavior, sexual identity is entirely subjective to the individual who asserts it. Sexual identity is sometimes used to refer to people who are transgender or nonconforming, but these two terms are more closely affiliated with a person’s gender identity. Additionally, sexual orientation includes a host of social and cultural implications that are often defined by clothing, make-up, community engagements, and a host of other factors that vary regionally and culturally.

The sexual identity of trans people is not easily reducible to the usual categories of gay and straight. For example, a transwoman who is attracted to males may think of herself as gay, as her sexual object choices are the same sex as her natal sex. Or she may think of herself as heterosexual, as she now identifies as a female and is attracted to males. It is also not uncommon for some transmen to be attracted to cisgender gay men and even consider themselves gay men. This is why the concepts of “androphilia” and “gynephilia” are growing in popularity, as they are words which designate object choice without reference to the sex or gender of the subject.

Many male-to-female trans persons have been attracted to women for their entire lives, to the extent that they want to become female themselves. Their experiences fall under the typology known as “autogynephilia,” which describes the sensation of feeling attracted to oneself, or the idea of oneself, as a woman [63,71,72,75,76]. Autogynephilia is a term that came to wide public consciousness with J. Michael Bailey’s 2003 book, The Man Who Would Be Queen: The Science of Gender-Bending and Transsexualism, and has amassed considerable controversy through the criticisms of numerous high-profile trans rights activists [72,70]. Criticisms of the concept of autogynephilia include the belief that this typology pathologizes transgenderism, reduces transitioning to a merely sexual act, and reinforces the stereotype that transwomen include many straight men attempting to “invade” women’s spaces [70,73,74]. It’s true that unfortunately both social conservatives and TERFs (Trans Exclusionary Radical Feminists) have co-opted the use of this term to defend their ideologies [77,78], however, the concept of autogynephilia alone does nothing to support such bigotry, and should not be dismissed purely because of how certain groups may misappropriate it. 

Sexual identity is different from attraction and behavior from a research perspective as well. The majority of research concerning sexual identity uses self-report measures. This means that once a person has identified themselves as homosexual, they will then be tested or studied with their gay identity being held as a constant while scientists use more quantitative measures like sexual attraction and behavior to isolate findings or origins of their orientation. The most popular and historically utilized form of self-report is the Kinsey Scale. An important thing to note about sexual identity is that although it implies particular types of sexual behavior or attraction, it does not exclusively guarantee or predispose either of those things: a person may identify as gay, but in practice be asexual in terms of personal attraction and celibate in behavior. The only person who can assert sexual identity is the individual claiming it. No amount of science can determine an individual’s identity.

2. Sexual attraction

Sexual attraction defines who and what individuals are attracted to. A person’s attraction can include particular types of people, genders, bodies, ages or social classes, certain sexual activities, fantasies, preferred social contexts for finding partners, and autoerotic attractions, just to name a few. Other types of sexual attraction include playing a dominant or submissive role within a sexual or romantic encounter, pursuer or pursued, and more masculine or feminine. These types of sexual attitudes are sometimes influenced by traditional gender norms which can play a role in someone’s sexual attraction, but some individuals are also attracted to partners who deviate from gender-typical behavior. Sexual arousal patterns motivate sexual behavior, which is the most common and fundamental basis for sexual self-identification [1]. There is no evidence that suggests individuals can consciously alter their physical arousal (most commonly detected in the genitals) to fit a certain sexual identity label [1].

Most scientific research into sexual attraction, based on physiological sexual arousal to various types of stimuli, uses the terms androphilic and gynephilic: the former representing people who are attracted to cisgender men and the latter attracted to cisgender women [1]. Research has tended to neglect transgender or gender-atypical persons as both subjects and objects of desire. Although complicated, this is integral to understanding sexual attraction, especially amongst LGBTQ+ youth.

“[All of us] have come to desire bodies and genitals within specific social contexts pregnant with ‘significant cultural and erotically charged meanings.’ In other words, what [we] want isn’t the “raw fact” of a [person’s] body, but what it represents in a certain context” [2].

For the most part, sexual attraction has been measured through genital response. The most common application is through PPG (penile plethysmography) assessments of men, a technique for assessing penile erection response to sexual stimuli, invented by Kurt Freund in 1963 [1]. The most common uses of the PPG assessment have been in diagnosis for erectile dysfunction and the detection for pedophilia among men convicted of sex offenses [1,13,14). Female genital responses measured through VPP (vaginal photoplethysmography) are neither as category-specific or reliable as men’s and thus have not been used to draw any particularly compelling conclusions about causation for female sexual attraction [1]. One explanation for this is that female sexual orientation is less category-specific than males’, which aligns with statistics that find that more women are bisexual than men [1]. Another reason is that women have been found to be influenced more strongly by considerations of love and intimacy, an individual’s life story or culturally based identity, and socially prevalent sexual scripts [27]. This broadens the category of people, activities, or things that women find sexually attractive, and are not easily measured with visual stimuli like pornography. 

3. Sexual behavior

Sexual behavior consists of sexual activity and interactions between persons of the same sex, a different sex, or both [1], but notions of same sex and different sex become complicated and inadequate in the case of trans or genderqueer individuals, who may prefer cisgender partners of either their own natal sex or their gender identity, or in some cases other trans and genderqueer folks. For contemporary rainbow youth, their sexual behavior and how it is categorized are personal to the individual participating in it, not a larger means of identity-classification dictated by science or politics.

There are circumstances where sexual behavior is subject to influence from an individual’s surroundings and position in life. This is one of the largest differences between sexual behavior and orientation/attraction. For example, some young people might engage in homosexual activity or pursue homosexual relationships because they are in sex-segregated environments such as boarding schools, the military, or prison [1].

Some may also do so because they lack opportunities with the opposite sex; similarly, some gay youth may experiment with opposite-sex partners because they are isolated in rural communities and do not know any other gay persons in their social environment. Sexual behavior can often be circumstantial, especially as it relates to sexual orientation and attraction. Our desires and identities change throughout our lives. It is only fitting that our sexual behavior would evolve alongside these other parts of ourselves.

The two most prominent kinds of empirical studies that have been used to investigate genetic influences on sexual orientation are twin studies and molecular genetic studies. Twin studies have been used to compare the importance of genetic and environmental influences on sexual orientation. Twins are ideal for this because they give scientists the opportunity to compare identical genetics within identical or variant environments. Thus, if two people with identical genes grow up to have different sexual orientations, there is room to conclude that this difference is due to environmental factors.

Unfortunately, early-separated monozygotic, or MZ (identical) twins are very rare. Separated twin pairs where one twin is straight and the other queer are even more uncommon. Studies that relied on this model are limited to a small number of case reports and thus have insufficient evidence to draw firm conclusions [40].

The “classical twin design” is much more feasible for scientists. This design depends on the two different kinds of twins: MZ and dizygotic (DZ) twins (also known as fraternal twins) [1]. Unlike MZ twins that share 99% of their genes, DZ twins share half. The classical twin design estimates the magnitude of genetic influences and two different kinds of environmental influences: shared and nonshared environments.

It should be noted that all twin studies have assessed sexual orientation via self-report. These studies have collected data from twin registries and probability sampling, like random phone sampling, and explicit recruitment of homosexual or non-heterosexual twins via advertisement or other means of outreach [1]. Although sampling bias remains a prominent concern for twin studies, they have collectively gathered enough evidence to support a genetic influence on sexual orientation. Identical twins, who share the same genes, are much more likely to share the same sexual orientation than are non-identical twins [43]. The best estimate of the magnitude of genetic effects on sexual orientation is moderate. This is unsurprising due to evolutionary pressure against genes that diminish opportunity for reproduction, which genes for homosexuality have the likelihood to do [23].

Molecular genetic studies have been difficult to replicate for many reasons. Part of this is due to the genetic phenomenon of heterogeneity, which is the fact that different genes can lead to the same outcome [1]. This makes it very difficult to discern whether or not a singular gene is responsible for observed differences between subjects. Amongst previous molecular genetic studies, sample sizes have often been too small to produce significant findings. The last prominent molecular genetic study looking to find a linkage between a previously identified region on chromosome 8, Xq28, included 409 pairs of homosexual brothers. Although this 2014 study helped to replicate findings from the first of its kind by Dean Hamer in 1993, the findings have still been considered inconclusive [25]. These two factors, and repeated failure to replicate other significant findings, have led to a shift from searching for individual linkages in DNA patterns to genome-wide association studies (GWAS) [1].

The most recent statistically significant GWAS findings related to the question of whether gayness is genetic were published in the Summer of 2019 [12]. The study collected DNA from 477,000 adults from the United States and the UK. Although some genetic similarities were found in subjects who reported having same-sex sexual experiences and attractions, none of the data were conclusive in providing proof of a “gay gene.” The researchers found five single points in the genome that seemed to be common among people who had at least one same-sex experience, but taken together these genetic markers explained less than 25% of the differences in sexual activity among people in the study [44]. Specific genes may affect different parts of an individual’s sexual makeup, such as the strength of sex drive and gender orientation [60].

Genetic explanations for sexuality differences also relate to evolution, as genes that reduce likelihood of reproduction diminish over time. There have been significant findings related to the sexually antagonistic gene hypothesis (SAGH), which holds that genes associated with the development of male homosexuality result in decreased reproduction amongst the heterosexual men who host that genetic makeup, but not females. The female relatives of homosexual men are especially likely to carry the same genes that reduce masculine performance, but make females predisposed to reproductive success. This in turn balances the diminished reproductive success of their homosexual male relatives [1].

The strongest support for the sexually antagonistic gene hypothesis has been collected in Western Europe, where maternal aunts of homosexual men have repeatedly exhibited elevated reproductive output compared to those with no homosexual children or nephews [10]. Yet, this research is still limited because sexually antagonistic selection does not fully counteract the reproductive deficits associated with male homosexuality. Two studies in 1978 and 2014 were able to measure the severity of these deficits which overwhelm the sexually antagonistic gene hypothesis’ ability to provide a comparatively positive reproductive output [25,26].

There are various hypotheses that connect hormonal influences to differences in sexual orientation amongst humans. The hormonal hypothesis has had the largest success in connecting a singular mechanism to the differences in sexual identity, attraction, and behavior. The most popular of hormonal hypotheses are those that involve prenatal hormone circulation processes in the mother’s womb that influence physical and mental sex differences.

Fetuses whose brains are exposed to high levels of androgens, typically a product of high testosterone, are likely to be sexually attracted to women in adult life. Fetuses whose brains are exposed to low levels of androgens are more likely to be sexually attracted to men in adult life [28]. There is also research that supports the clarification that it is not the hormones themselves that influence these differences, but the brain’s sensitivity to hormones [27].

Many studies have been done including individuals with congenital adrenal hyperplasia (CAH), in which human fetuses are exposed to irregularly high levels of androgens. Meyer-Bahlburg and associates conducted a study in 2008 of women with CAH [28]. Typically, women affected with CAH will have higher androgen levels during prenatal development, which results in higher levels of testosterone compared to unaffected women. Two groups of affected and unaffected women in this study were administered Sexual Behavior Assessment Schedule tests.

The conclusions from this study were that women with CAH, and thus higher levels of testosterone in their systems, were more likely to experience same-sex attraction and behavior than were the unaffected women. This study also calls into question the degree of genetic influence, since the unaffected sample groups were sisters and cousins of the affected women. Although CAH does not exclusively indicate non-heterosexual attraction and behavior, women with CAH experience higher levels of homosexuality and bisexuality compared to the general and unaffected female populations, including those to whom they are related [28]. Thus, hormones have a higher level of influence than genetics in this particular study.

Neuroscientist Simon LeVay has focused on the hypothalamus, also known as the medical preoptic area, as it relates to the regulation of sexual behaviors and attractions [30]. The majority of this work was focused on males. Within the medial preoptic area is a cell group named INAH3 that is typically larger in males than females. This difference has been found to be caused by sex differences influenced by circulating sex hormones during the prenatal development period. LeVay measured the volume of INAH3 tissue in autopsies of gay and straight men. LeVay found that the volume of the tissue was significantly smaller in gay men than in straight men and that the size of the INAH3 in gay men was similar to that of straight women [30]. This study has been replicated with similar findings.

The way that the hypothalamus functions has also been observed to be different in gay and straight people. A particularly interesting study by a Swedish research group used a PET scanner to study how different brains reacted to smelling odorous compounds derived from human fluids that act as pheromones, like sweat [31]. There is a compound called androstadiene (AND) that is derived from male armpit sweat. The hypothalamus was observed to be active in both gay men and straight women when sniffing AND.

The same part of the brain was found to be inactive in straight men and lesbians when sniffing AND. Another group of researchers obtained opposite results when asking subjects to smell a compound found in female body sweat: the hypothalamus was active in straight men and gay women and inactive in gay men and straight women [32,33]. However, these findings have not been replicated and still fail to determine if these brain processes are a product of the biological process of brain development or unconsciously remembered scents from pleasurable social and sexual experiences throughout the subject’s life.  

Arguably the most popular hormonal study resulted in the fraternal birth order effect hypothesis. The fraternal birth order effect implies that the androgens a mother’s body is capable of supplying to her fetus diminishes with each male child she carries. Per this hypothesis, the youngest brother of four is the most likely to be homosexual, and the eldest the least. A man without any older brothers has a 2% chance of being homosexual, a man with one older brother a 2.6% chance, and with two, three, and four older brothers, the chances are 3.5%, 4.6% and 6%, respectively [1]. Meanwhile, based on population-level data gathered from the Netherlands, a very recent study found that 0.73% of men who are the youngest of five siblings entered a same sex union, compared to just 0.35% of men who are the eldest of five siblings” [61].

A few other studies have been used to test the hormonal hypothesis for sexual orientation. Savic and Lindstrom found that there was a difference in the relative size of the left and right cerebral hemispheres amongst gay and non-gay individuals [34]. There have also been differences spotted in the function of the inner ear [35], eye-blink reflexes [36], relative lengths of the fingers [37,38], and the ratio of arm length to height [39]. None of these characteristics are or should be used to diagnose someone’s sexual orientation. Instead, they reflect noticeable differences between large sample populations of homosexual and non-homosexual subjects. Most applicable to our discussion, these anatomical differences are often considered gender atypical and lend themselves to consideration of hormonal influences during development and later in life.

       Marc Breedlove, a professor of psychology, compared two areas of study of sexual orientation: pre-natal androgen levels and finger length [51]. Most studies of pre-natal androgen levels have been consistent with the scientific and cultural understanding that homosexual women are more masculine and homosexual men more feminine than their straight counterparts. This has been postulated to be a direct result of androgen levels, which relate to testosterone levels, in sex development processes. In most individuals, the index finger is slightly shorter than the ring finger, but several studies have found that in the right hand, this difference is accentuated by higher levels of androgens during fetal development [51]. Thus, most men would have a larger length difference between their ring and index finger, whereas most women would have two fingers of identical, or very similar, length. This finding is consistent with other studies that associate gayness in women with higher levels of androgen during prenatal development.

Breedlove collected data on 720 people and found that, on average, gay women had index and ring finger lengths closer to that of straight men. Breedlove’s observed patterns were less consistent amongst the men in his study. There was not a significant relationship between finger length and sexual orientation. However, when measuring finger lengths, some of the gay men in his study appeared to have been exposed to greater than normal levels of fetal androgen than the typical male [51]. This complicates our understanding of masculinity and femininity as they relate to both sexuality and gender. According to Breedlove’s study, some hypermasculine, high-testosterone men are also homosexual. This should not surprise anyone who has ever visited a gay leather bar and witnessed its culture of hyper-masculinity. Some men whose high testosterone levels condition risk-taking and promiscuity gravitate toward the gay lifestyle because it offers more opportunity and variety than mainstream heterosexual socialization. This may also explain the conduct of some married bisexual men who, in addition to maintaining a regular sexual relationship with their wife, also seek gay sex “on the down low.” Male same-sex behavior can thus be influenced by either a deficiency or excess of androgens. All in all, we still don’t know entirely how and to what degree hormones affect sexual orientation.

Discussions of hormonal and genetic influences on sexuality need to be complemented by consideration of environment and socialization. Some genes trigger what are known as “epigenetic” effects – effects which activate only in the presence of certain environmental stimuli (like a need to develop a certain skill) or stressors (like an infection), and hormone levels can fluctuate  throughout a person’s life. So, do people’s genes and hormones function the way they do because people were “born that way” or because they grew to be that way? It is not necessarily an either/or question.

Sexual identity certainly has environmental influences, inasmuch as labels for one’s sexual makeup are cultural products that vary from one era and society to another. For example, in the 1970s during the height of Second Wave feminism, a number of women expressed their ideological resistance to patriarchy by entering lesbian relationships [45]. Many of these women returned to relationships with men, but this goes to show that sexual identity changes and moves through time alongside the person it belongs to.

“It is certain, however, that socialization strongly influences how gay people think of themselves and how they live their lives” [27].

Environment and social factors also relate to sexual behavior and attraction in a different way. Individuals who attend gender-separated boarding schools have more homosexual experiences during that time than people who do not attend those schools. However, these people are no more likely to be gay in adulthood [46]. 

An exclusively environmental or social-causal hypothesis for homosexuality was challenged with a controversial and arguably unethical experiment performed upon intersex children whose external reproductive organs were reassigned from male to female upon birth or before the age of 2. All seven children were subsequently raised as females, culturally and environmentally speaking. All seven children whose sexual organs had been surgically altered or removed grew up to be attracted to women, even after being explicitly raised as girls [5-8]. If sexual orientation is entirely socialized, then at least one or the majority of these children would have reported being attracted to men. Many other studies likewise weaken the argument that parental influence or relationships influence non-heterosexuality [27,41,42,45].

Although it is a common political sound bite, there is no evidence that homosexuals “recruit” younger teens and children into their lifestyles. Although early non-heterosexual experiences are much more common for rainbow youth than their straight peers and are often with a somewhat older partner, they are a result, not a cause, of sexual orientation. This remains true even in circumstances where individuals’ non-heterosexual identity emerges later in life [47]. A study from 1981 found that a large portion of non-heterosexual people recalled experiencing homosexual feelings before ever engaging in homosexual behavior by at least 3 years [47].

However, it is important to note the disproportionate sexual abuse of gender non-conforming or non-heterosexual children. Younger sexual experience, especially if it is traumatic, does not influence sexual orientation. Rather, it provides an example of the ways that sexual orientation and gender non-conformity produce certain social vulnerabilities [1].

A study of 33,902 individuals found that non-heterosexual adults of both sexes were much more likely than heterosexual adults to have experienced childhood sexual abuse: 38.1% of lesbians, 43.5% of bisexual women, and 14.2% of heterosexual women; 18.6% of gay men, 19% of bisexual men, and 4.6% of heterosexual men [48]. It is often thought that early abuse by males causes some women to distrust men and therefore prefer female partners. However, the authors of this study rejected any interpretation of their data to support abuse as the cause of non-heterosexual orientation and rather pointed to signs of gender non-conformity making children especially vulnerable to predation. “For example, they may be recognized by older opportunistic individuals with same-sex desires. Alternatively, they may be victimized by others who dislike gender nonconformity” [48].

In this particular study, childhood sexual abuse is defined as “sexual experiences with an adult or any other person younger than 18 years when the individual did not want the sexual experience or was too young to know what was happening” [48].  This definition does not count as abuse all age-discrepant sexual experiences. Even if illegal, these encounters are more often consensual and non-traumatic than non-consensual [49]; some rainbow adolescents actively seek out older partners with more experience [64,65,66].

So far, we have been peeling through the layers of human sexuality, and have found that it results from an intricate combination of hormonal and genetic predisposition as well as environmental interactions and opportunities. Altogether it has been divided up into three main tiers: attraction, behavior, and identity. We can also discuss what seems to be a fourth stratum, incorporating the free will and principles of the sexual subject in relation to their orientation. This human characteristic can take several names: sexual self-concept, sexual attitudes, sexual ethics, self-governance, etc., but “sexual values” seems the most useful term. Sexual values refer here to the way one situates their sexuality in line with their personal attitudes and beliefs. This is not the same as sexual behavior, in that one’s values are not necessarily mirrored by one’s actions, nor is it the same as sexual identity, as one can acknowledge the ongoing patterns of one’s attractions without making any value judgements about the morality of their consummation.

We see the effects of freely adopted sexual values in play all around us, and their practice includes, but is not limited to people who take monogamous marriage vows, celibate gay Christians, monks and nuns who take vows of celibacy, virtuous pedophiles/“NOMAPs,” (Non-Offending Minor Attracted People), hookup culture/pickup artistry, “incels” (Involuntary Celbates), “MGTOW” (Men Going Their Own Way), polyamorists, and young men who are “gay-for-pay.” Sexual values can be said to bridge the most public aspects of human sexuality with the most intimate parts of the self. The phenomenon of bisexuality can be used to further elucidate the nature of sexual values. Although bisexuality has been attached to the core of queer thought for so long it has practically become provincialized, bisexuality has unique implications for understanding the link between inner sexual reality and public presentation.

Until recently, research on sexual orientation ignored bisexuality by either excluding bisexual people from studies or combining bisexual individuals with monosexual subjects [1]. The distinction between sexual behavior and orientation is integral to approaching bisexuality. For instance, transitional bisexuality, the adoption of a bisexual identity preceding the assertion of an identity as homosexual, is one path to an adolescent’s developing self-awareness. However, other inexperienced young people who first consider themselves exclusively gay or lesbian later discover that they are also capable of being attracted to and forming a relationship with a partner of the opposite sex.

Discovering causes for bisexuality has proven more difficult, especially when measuring sexual attraction. Self-report methods for obtaining data must be particularly nuanced, as self-recognition of bisexual identity has been found to emerge from a long process of trying to make sense of divergent current and previous attractions that are contradictory to either a purely homosexual or heterosexual orientation [1]. Other self-report findings have indicated that some individuals may feel it is easier to admit homosexual feelings if they are not entirely “ruling out” the possibility of heterosexual attractions and relationships [1].

Bisexuality and other non-monosexualities are emblematic of the way society attempts to categorize realities via certain actions, and how easily these attempts can be contradicted and subverted. The gay and the straight spheres have each had an uncomfortable time incorporating bisexuality into their sexual narratives: even though they can fit into both the homosexual and heterosexual “lifestyles,” bisexuals are always potential defectors. They have a certain freedom to choose partners of either sex that exclusively gay and straight persons feel they lack.

Although bisexuality was once largely dismissed by the gay community due to its lack of potential for political mobilization, the percentages of self-reported bisexuality, as well as pansexuality, heteroflexibility, bi-curiosity, and “mostly straight” identity among the Gen Z population shows the increasing understanding of sexuality as refractable through the lenses of sex, gender expression, gender presentation, age, developmental period, context, relationship, community, time, and place.    

It must also be realized that sex and sexual relationships are often deployed for reasons of expressing personal sentiments or engaging in political theater such as women who form intimate relationships with other women to show feminist commitment. This is not dissimilar to the ideological performance of people who rape to express dominance, people who divorce in criticism of the institution of marriage (such as author Charles Webb and his wife Eve Rudd), people who participate in “No-Nut November,” etc.

Also characteristic of an individual’s autonomy in interacting with their social environment are religiously influenced individuals who choose to practice complete abstinence from non-heterosexual behavior out of obedience to their faith. Some individuals who might have been predisposed nevertheless refrain from identifying as non-heterosexual or engaging in non-heterosexual behavior due to other social obstacles they faced when young. A 2013 study of 1,518 secondary school students of mostly Western backgrounds found that religious condemnation of same-sex behavior was even higher amongst youth who reported having same-sex attractions [59]. This provides evidence of internalized homophobia that is often experienced by young people raised in highly religious environments, most of which denounce homosexuality or other unconventional orientations.

Similar to teaching children about consent at an early age, it is important that children of any age understand to lean into relationships and exchanges that make them feel good, seen, and validated. Sometimes these relationships fit different categories than those we are most comfortable using, but this does not invalidate experience. It is important to recognize that all adolescents crave freedom to choose how they explore their sexuality in a safe way and with whom, and isolated lesbian, gay, or trans adolescents will have fewer ideal options than most straight cisgender teenagers do; you cannot be the one to pick their companion(s) for them. Some level of experimentation is a normal part of discovering sexuality, and this need relates much more to an adolescent’s developing sense of personal autonomy than it does their genetics or hormonal influences.

Statistically, gender non-conforming children are more likely to identify as non-heterosexual in adulthood. Thus, one may assume that similar genetic, hormonal, and environmental variables influence gender as much as sexuality. Childhood Gender Non-conformity refers to when a child often behaves in a manner typically associated with the other sex. Among boys, this nonconformity may present as the following phenomena: preferring clothing associated with girls, desiring to have long hair, playing with dolls, disliking competitive sports and rough play, preferring girls as playmates, and exhibiting elevated separation anxiety [1].

For young girls, gender non-conformity may present with the following manifestations: preferring clothing associated with boys, showing interest in competitive sports and rough play, and lacking interest in makeup and conventionally female toys such as dolls [1]. Neither of these lists are complete or definitive, and children should be given freedom to experiment and determine which clothing and forms of play they like best. Gender non-conforming behavior usually emerges at preschool age and resolves itself soon after puberty [1]. Sometimes it does not and lasts into adolescence and adulthood; when it causes psychological distress, it generates “gender dysphoria,” in which case a teen may need counseling to determine suitability for some form of gender transition. Gender-Variant and Gender-Questioning Youth

It is important to remind ourselves that gender non-conformity is a matter of degree, not of kind [1]. Some cases of gender non-conforming behavior have been observed in children as young as 2. In fact, gender non-conforming behavior typically emerges despite conventional socialization [1]. A 2008 study found that most gender non-conforming children who choose to remain in their natal sex do become gay adults [53]. Still, it is not possible to predict with certainty the future sexual or gender identity of even the most gender non-conforming children.

The hormonal hypothesis could explain why non-heterosexual people are, on average, gender-atypical in a variety of ways, some gay men being more feminine and others hyper-masculine. It also is easier to understand because gendered behavior is often associated with levels of hormones like estrogen and testosterone, related to prenatal androgen levels circulating during a sensitive period of fetal development. For example, women with congenital adrenal hyperplasia are more likely to exhibit gender-nonconforming traits and behavior than unaffected women [29]. In a self-descriptive study of gay and bisexual men, non-heterosexual men were more likely to describe themselves as more feminine than straight men [54]. In the same study, lesbians and bisexual women describe themselves as less feminine than do straight women [54].

Twin studies have produced interesting findings about gender non-conformity from retrospective accounts of childhood [19,20,21]. The probability that identical twins are concordant for sexual orientation is unrelated to the degree of non-heterosexual twins’ childhood gender non-conformity. This suggests little evidence to support the belief that homosexuality and gender non-conformity, when they present simultaneously, are heritable. However, identical twin pairs with different sexual identities reveal significant differences in childhood gender non-conformity, with the homosexual twin recalling higher levels of gender non-conformity compared to the heterosexual twin. This suggests that non-shared environmental factors, rather than genetics, affect difference in sexual identity early in development.

For more on the possible causes of gender variance and transgender identification, see the discussion in our section on gender-variant and gender-questioning youth. Gender-Variant and Gender-Questioning Youth 

Making any effort to change someone’s sexual identity is harmful. As a parent, it is important to remind yourself that you are not directly responsible for your child’s identity. Even if hereditary or hormonal factors may be involved, do not blame yourself for insufficient efforts to masculinize a male child or condition femininity in one who is born female. You should not feel ashamed to let your child experiment with different modes of self-expression that may not be gender-normative. Every child is an autonomous and developing person who has learned from their surroundings outside the home, adapted to inborn behaviors and instincts, and created their own understanding of themselves based on what they have read and seen in others.

If you find yourself confused or frustrated about your child’s identity, instead of making efforts to change or diminish who they are, try to understand them. Part of what has brought you to this website is an initiative to learn more about your child’s identity and community. This is an integral step towards making sure that you can support them in who they are. There is only potential to harm, distance, and squander your parent-child relationship by taking steps to change or deny their autonomy as an individual.

If you don’t know where to start in the wake of confusion and frustration, begin by asking questions. First, ask yourself whether you feel upset or disappointed by your child’s LGBTQ+ identity. Can you identify anything within your life experience that might lead you to be biased towards LGBTQ+ individuals? Have you had experiences where pieces of your identity do not align with the greater social framework in which you live? How did that make you feel? What did you do to adapt?

Second, ask your child questions about themselves. You can learn plenty about your child without asking them directly about their sexual behavior and attractions. Try learning about their favorite activities, TV shows, artists, or clothing style. An individual’s sexual identity is only a piece of their larger self. Once you can begin to understand the layers of your child’s identity, you will then have established more grounds on which to understand their sexual identity. It is also important to remain respectful of your child’s personal zone of privacy: how much a child wants to share with you about their sexual feelings and when depends on factors that may not be within your control.

Sex and gender are not the most comfortable topics for a child of any age to talk about with a parent. Before pressing for details, try initiating general conversations about sexual safety and protection. If you feel like you need help with this, or would like some pointers to get the ball rolling, we’ve gathered some links you may find beneficial: https://www.moms.com/talk-teenagers-about-sensitive-topics/,   https://www.commonsensemedia.org/articles/how-to-talk-to-kids-about-difficult-subjects,    https://raisingchildren.net.au/teens/communicating-relationships/tough-topics/difficult-conversations-with-teen.  

Efforts to change your child’s self-proclaimed sexual or gender identity are almost always counterproductive. Historically one of the most popular efforts to change these integral pieces of a person’s identity is “reparative” or “conversion” therapy. As mentioned above, conversion therapy is defined as a range of dangerous and discredited practices that claim to change a person’s sexual orientation, gender identity or gender expression [55]. Although the majority of mainstream medical and mental health organizations have rejected these practices, a small minority of practitioners continue to conduct conversion therapy. Minors are particularly vulnerable to the repercussions of conversion therapy, which include depression, anxiety, drug use, homelessness and suicide [55,67,68,69]. Minors are also vulnerable because they have no way to dictate whether or not they are subject to these practices. It is important to consider that as a parent, you are responsible for protecting your child from the harm that these methods cause.

Faith-based conversion therapies, meanwhile, encourage children to pray for their sexual attraction and behaviors to be different [56]. Some of these efforts use language from religious texts that target “sexual brokenness,” “unwanted same-sex attractions,” or “gender confusion.” Any and all claims that conversion therapy works or provides any effective change to a person’s identity have been refuted by dozens of medical and mental health organizations, including but not limited to the American Academy of Child Adolescent Psychiatry, American Academy of Pediatrics, American Association for Marriage and Family Therapy, American College of Physicians, American Counseling Association, American Medical Association, American Psychiatric Association, American Psychoanalytic Association, American Psychological Association, American School Counselor Association, American School Health Association, National Association of Social Workers, and more. Read the full list and their testimonies here.

According to the Trevor Project’s 2020 National Survey on LGBTQ Youth Mental Health, 10% of LGBTQ youth reported having undergone conversion therapy [56]. 78% of those reported having this therapy under the age of 18. The same study also concluded that youth who reported undergoing conversion therapy were more than twice as likely to attempt suicide as those who had not [57]. Furthermore, of the sample of LGBTQ youths pressured into conversion therapy, 35% reported that it was a parent or caregiver who made this decision [57].

There are also numerous cases wherein a religious official or psychiatrist has been approached by LGBTQ individuals of their own volition in an effort to change their sexual identity. Even in cases of clients who expressed a wish to change their sexual identity, the individual’s mental health and relationship to their family often deteriorated [58]. Therapy can provide patients help in dealing with the discomfort and unpleasant effects of sexual desires of which their religious or social community disapproves, and can sometimes help them remain celibate or enhance already existing bi-sexual tendencies that will not offend the tenets of their religious faith. But it almost never frees a person from their attractions.

We encourage you to ask your children questions about their lives and their general happiness. Even though 1 in 5 of the new generation identify as LGBTQ+, they still live in a world where gayness is considered wrong by many people, so there are many aspects of their identity that might lead them to struggle or engage in high-risk behavior. You can educate your children with what you have learned from this website.

So, while sexuality is largely innate and determined from a very early age, it is also context sensitive and highly subject to fluctuations, both in how it is experienced and how it is defined. Some well-meaning parents, hoping to show support for their gay or trans child, may repeatedly affirm the perfect naturalness of homosexuality and transgenderism and tell them that they don’t need to change. However, this may be interpreted as telling them they can’t change, or they shouldn’t change, and this can make them even more confused as they experience new things, taste new sensations, and seek to identify themselves in new ways. Embrace who they are, but be careful not to box them in from who else they can be and teach them to never be afraid of being surprised.  

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