Sexual Orientation and Gender Identity

Learning Objectives

  • Describe variations in sexual orientation and gender identity

Sex and Sexual Orientation

As mentioned in the introduction, sex assigned at birth refers to how one’s anatomy, physiology, hormones, and genetics are classified. Gender identity is a person’s sense of their own gender, or sociocultural classification (i.e., man, woman, or another gender) based on, or in opposition to, their sex assigned at birth (i.e., male, female, or intersex). Sexual orientation is an enduring pattern of romantic or sexual attraction (or a combination of these) to persons of the opposite sex or gender, the same sex or gender, or to both sexes or more than one gender. These attractions are generally subsumed under heterosexuality, homosexuality, and bisexuality, while asexuality (the lack of sexual attraction to others) is sometimes identified as the fourth category.)

According to the American Psychological Association, sexual orientation “also refers to a person’s sense of identity based on those attractions, related behaviors, and membership in a community of others who share those attractions.”[1] As a sexual orientation, heterosexuality is “an enduring pattern of emotional, romantic, and/or sexual attractions” to persons of the opposite sex; someone who is heterosexual is commonly referred to as straight.[2] As a sexual orientation, homosexuality is “an enduring pattern of emotional, romantic, and/or sexual attractions” to people of the same sex. The most common terms for homosexual people are lesbian for females and gay for males, but gay also commonly refers to both homosexual females and males. Bisexuality is romantic attraction, sexual attraction, or sexual behavior toward both males and females. It may also be defined as romantic or sexual attraction to people of any sex or gender identity, which is also known as pansexuality. Varying definitions and strong social norms about sexuality can make sexual orientation difficult to quantify.

While the majority of people identify as heterosexual, there is a sizable population of people within the United States who identify as either homosexual or bisexual. Research suggests that somewhere between three and 10% of the population identifies as homosexual (Kinsey, Pomeroy, & Martin, 1948; LeVay, 1996; Pillard & Bailey, 1995).

A photograph shows two people holding hands.

Figure 1. Between three and 10% of the adult population identifies as homosexual. (credit: Till Krech)

Issues of sexual orientation have long fascinated scientists interested in determining what causes one individual to be heterosexual while another is homosexual. For many years, people believed that these differences arose because of different socialization and familial experiences. However, research has consistently demonstrated that family backgrounds and experiences are very similar among heterosexuals and homosexuals (Bell, Weinberg, & Hammersmith, 1981; Ross & Arrindell, 1988).

Genetic and biological mechanisms have also been proposed, and the balance of research evidence suggests that sexual orientation has an underlying biological component. For instance, over the past 25 years, research has demonstrated gene-level contributions to sexual orientation (Bailey & Pillard, 1991; Hamer, Hu, Magnuson, Hu, & Pattatucci, 1993; Rodriguez-Larralde & Paradisi, 2009), with some researchers estimating that genes account for at least half of the variability seen in human sexual orientation (Pillard & Bailey, 1998). Other studies report differences in brain structure and function between heterosexuals and homosexuals (Allen & Gorski, 1992; Byne et al., 2001; Hu et al., 2008; LeVay, 1991; Ponseti et al., 2006; Rahman & Wilson, 2003a; Swaab & Hofman, 1990), and even differences in basic body structure and function have been observed (Hall & Kimura, 1994; Lippa, 2003; Loehlin & McFadden, 2003; McFadden & Champlin, 2000; McFadden & Pasanen, 1998; Rahman & Wilson, 2003b). In aggregate, the data suggest that to a significant extent, sexual orientations are something with which we are born.

Although the field once stigmatized non-heterosexual orientations, we now know that homosexuality and bisexuality are in no way related to mental health. Sexual orientation is neither chosen nor changed. 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. While some people believe that homosexual activity is unnatural, scientific research shows that homosexuality is a normal and natural variation in human sexuality and is not in and of itself a source of negative psychological effects. There is insufficient evidence to support the use of psychological interventions to change sexual orientation.

Misunderstandings about Sexual Orientation

Regardless of how sexual orientation is determined, research has made clear that sexual orientation is not a choice, but rather it is a relatively stable characteristic of a person that cannot be changed. Claims of successful gay conversion therapy have received wide criticism from the research community due to significant concerns with research design, recruitment of experimental participants, and interpretation of data. As such, there is no credible scientific evidence to suggest that individuals can change their sexual orientation (Jenkins, 2010).

Dr. Robert Spitzer, the author of one of the most widely cited examples of successful conversion therapy, apologized to both the scientific community and the gay community for his mistakes, and he publicly recanted his own paper in a public letter addressed to the editor of Archives of Sexual Behavior in the spring of 2012 (Carey, 2012). In this letter, Spitzer wrote,

I was considering writing something that would acknowledge that I now judge the major critiques of the study as largely correct. . . . I believe I owe the gay community an apology for my study making unproven claims of the efficacy of reparative therapy. I also apologize to any gay person who wasted time or energy undergoing some form of reparative therapy because they believed that I had proven that reparative therapy works with some “highly motivated” individuals. (Becker, 2012, pars. 2, 5)

Citing research that suggests not only that gay conversion therapy is ineffective, but also potentially harmful, legislative efforts to make such therapy illegal have either been enacted (e.g., it is now illegal in California) or are underway across the United States, and many professional organizations have issued statements against this practice (Human Rights Campaign, n.d.)

Link to Learning

Read this draft of Dr. Spitzer’s letter.

Watch It

Watch this video to learn about variations and differences in sex and gender expression.

You can view the transcript for “Sexual orientation and gender identity” here (opens in new window).

Gender Identity

Many people conflate sexual orientation with gender identity because of stereotypical attitudes that exist about homosexuality. In reality, these are two related, but different, issues. Gender identity refers to one’s sense of being male or female. Generally, our gender identities correspond to our chromosomal and phenotypic sex, but this is not always the case. When individuals do not feel comfortable identifying with the gender associated with their sex assigned at birth, then they experience gender dysphoria. Gender dysphoria, which we explore in the next section, is a diagnostic category in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) that describes individuals who do not identify as the gender that most people would assume they are. This dysphoria must persist for at least six months and result in significant distress or dysfunction to meet DSM-5 diagnostic criteria. In order for children to be assigned this diagnostic category, they must verbalize their desire to become the other gender.

Cisgender is an umbrella term used to describe people whose sense of personal identity and gender corresponds with their birth sex, while transgender is a term used to describe people whose sense of personal identity does not correspond with their birth sex. Approximately 1.4 million U.S. adults or 0.6% of the population are transgender according to a 2016 report.[3]

Many people who are classified as gender dysphoric seek to live their lives in ways that are consistent with their own gender identity. This involves dressing in opposite-sex clothing and assuming an opposite-sex identity. These individuals may also undertake transgender hormone therapy in an attempt to make their bodies look more like the opposite sex, and in some cases, they elect to have surgeries to alter the appearance of their external genitalia to resemble that of their gender identity (Figure 6). Transgender people who attempt to alter their bodies through medical interventions such as surgery and hormonal therapy are called transsexual individuals. They may also be known as male-to-female (MTF) or female-to-male (FTM). Not all transgender individuals choose to alter their bodies: many will maintain their original anatomy but may present themselves to society as another gender.

Photograph A shows Chaz Bono as a child. Photograph B shows Chaz Bono as an adult.

Figure 2. Chaz Bono, a transgender male, is a well-known person who transitioned from female to male. (a) In the 1970s, the world knew Chaz as Chastity Bono, the daughter of the famous entertaining duo Sonny and Cher; here young Chastity is pictured with Sonny. (b) Later in life, Chaz transitioned to align his physical body with his gender identity. (credit b: modification of work by "dvsross"/Flickr)

Cultural Factors in Sexual Orientation and Gender Identity

Gender is deeply cultural. Like race, it is a social construction with real consequences, particularly for those who do not conform to gender binaries. In order to describe gender as a concept, we need to expand the language we use to describe gender beyond “masculine” or “feminine.” Gender identity, or the way that one thinks about gender and self-identifies, can be woman, man, or genderqueer.

Gender expression, or how one demonstrates gender (based on traditional gender role norms related to clothing, behavior, and interactions) can be feminine, masculine, androgynous, or somewhere along a spectrum. Although gender has traditionally been considered in binary terms (male or female), increasingly gender is being seen as a spectrum; however, our vocabulary is still limited in terms of the ways in which we describe gender identity.

Issues related to sexual orientation and gender identity are very much influenced by sociocultural factors. Even the ways in which we define sexual orientation and gender vary from one culture to the next. While in the United States exclusive heterosexuality is viewed as the norm, there are societies that have different attitudes regarding homosexual behavior. In fact, in some instances, periods of exclusively homosexual behavior are socially prescribed as a part of normal development and maturation. For example, in parts of New Guinea, young boys are expected to engage in sexual behavior with other boys for a given period of time because it is believed that doing so is necessary for these boys to become men (Baldwin & Baldwin, 1989).

There is a two-gendered culture in the United States. We tend to classify an individual as either male or female. However, in some cultures there are additional gender variants resulting in more than two gender categories. For example, in Thailand, you can be male, female, or kathoey. A kathoey is an individual who would be described as intersexed or transgender in the United States (Tangmunkongvorakul, Banwell, Carmichael, Utomo, & Sleigh, 2010).

Dig Deeper: The Case of David Reimer

In August of 1965, Janet and Ronald Reimer of Winnipeg, Canada, welcomed the birth of their twin sons, Bruce and Brian. Within a few months, the twins were experiencing urinary problems; doctors recommended the problems could be alleviated by having the boys circumcised. A malfunction of the medical equipment used to perform the circumcision resulted in Bruce’s penis being irreparably damaged. Distraught, Janet and Ronald looked to expert advice on what to do with their baby boy. By happenstance, the couple became aware of Dr. John Money at Johns Hopkins University and his theory of psychosexual neutrality (Colapinto, 2000).

Dr. Money had spent a considerable amount of time researching transgender individuals and individuals born with ambiguous genitalia. As a result of this work, he developed a theory of psychosexual neutrality. His theory asserted that we are essentially neutral at birth with regard to our gender identity and that we don’t assume a concrete gender identity until we begin to master language. Furthermore, Dr. Money believed that the way in which we are socialized in early life is ultimately much more important than our biology in determining our gender identity (Money, 1962).

Dr. Money encouraged Janet and Ronald to bring the twins to Johns Hopkins University, and he convinced them that they should raise Bruce as a girl. Left with few other options at the time, Janet and Ronald agreed to have Bruce’s testicles removed and to raise him as a girl. When they returned home to Canada, they brought with them Brian and his “sister,” Brenda, along with specific instructions to never reveal to Brenda that she had been born a boy (Colapinto, 2000).

Early on, Dr. Money shared with the scientific community the great success of this natural experiment that seemed to fully support his theory of psychosexual neutrality (Money, 1975). Indeed, in early interviews with the children it appeared that Brenda was a typical little girl who liked to play with “girly” toys and do “girly” things.

However, Dr. Money was less than forthcoming with information that seemed to argue against the success of the case. In reality, Brenda’s parents were constantly concerned that their little girl wasn’t really behaving as most girls did, and by the time Brenda was nearing adolescence, it was painfully obvious to the family that she was really having a hard time identifying as a female. In addition, Brenda was becoming increasingly reluctant to continue her visits with Dr. Money to the point that she threatened suicide if her parents made her go back to see him again.

At that point, Janet and Ronald disclosed the true nature of Brenda’s early childhood to their daughter. While initially shocked, Brenda reported that things made sense to her now, and ultimately, by the time she was an adolescent, Brenda had decided to identify as a male. Thus, she became David Reimer.

David was quite comfortable in his masculine role. He made new friends and began to think about his future. Although his castration had left him infertile, he still wanted to be a father. In 1990, David married a single mother and loved his new role as a husband and father. In 1997, David was made aware that Dr. Money was continuing to publicize his case as a success supporting his theory of psychosexual neutrality. This prompted David and his brother to go public with their experiences in attempt to discredit the doctor’s publications. While this revelation created a firestorm in the scientific community for Dr. Money, it also triggered a series of unfortunate events that ultimately led to David committing suicide in 2004 (O’Connell, 2004).

This sad story speaks to the complexities involved in gender identity. While the Reimer case had earlier been paraded as a hallmark of how socialization trumped biology in terms of gender identity, the truth of the story made the scientific and medical communities more cautious in dealing with cases that involve intersex children and how to deal with their unique circumstances. In fact, stories like this one have prompted measures to prevent unnecessary harm and suffering to children who might have issues with gender identity. For example, in 2013, a law took effect in Germany allowing parents of intersex children to classify their children as indeterminate so that children can self-assign the appropriate gender once they have fully developed their own gender identities (Paramaguru, 2013).

Watch this news story to hear more about the experiences of David Reimer and his family.

Hear firsthand about the transgender experience and the disconnect that occurs when one’s self-identity is betrayed by one’s body. In this brief video interview, Chaz Bono discusses the difficulties of growing up identifying as male, while living in a female body.

Try It

Glossary

bisexual: emotional and erotic attractions to both same-sexed individuals and opposite-sexed individuals

cisgender: an umbrella term used to describe people whose sense of personal identity and gender corresponds with their sex assigned at birth

gender dysphoria: diagnostic category in DSM-5 for individuals who do not identify as the gender associated with their sex assigned at birth 

gender expression: how one demonstrates gender based on traditional gender role norms related to clothing, behavior, and interactions

gender identity: a person's sense of their own gender, or sociocultural classification (i.e., man, woman, or another gender) based on, or in opposition to, their sex assigned at birth

heterosexuality: an enduring pattern of emotional, romantic, and/or sexual attractions to persons of the opposite sex

homosexuality: an enduring pattern of emotional, romantic, and/or sexual attractions to people of the same sex

pansexuality: romantic or sexual attraction to people of any sex or gender identity

sexual orientation: emotional and erotic attraction to same-sexed individuals, opposite-sexed individuals, or both

transgender: a term used to describe people whose sense of personal identity does not correspond with their sex assigned at birth

transgender hormone therapy: use of hormones to make one’s body look more like the opposite-sex

transsexual: transgender individuals who attempt to alter their bodies through medical interventions such as surgery and hormonal therapy


  1. "Sexual Orientation & Homosexuality". American Psychological Association. 2020. Retrieved February 6, 2020.
  2. "Sexual orientation, homosexuality and bisexuality". American Psychological Association. Archived from the original on August 8, 2013. Retrieved August 10, 2013.
  3. [footnote]Flores, A., J. Herman, G. Gates, and T. N.T. Brown. "How many adults identify as transgender." The Williams Institute. http://williamsinstitute.law.ucla.edu/wp-content/uploads/How-Many-Adults-Identify-as-Transgender-in-the-United-States.pdf.