Do scientists study sexual orientation in order to ‘cure’ or ‘treat’ it?

Our study will look for genes that may influence some women in ways that they become lesbian, bisexual, straight, queer, etc. Sexual orientation is a fundamental trait of great scientific interest. Understanding the origins of sexual orientation will enable us to learn a great deal about sexual motivation, sexual identity, gender identity and sex differences. Our primary goals are scientific, but we also are hopeful for greater societal understanding. Earlier studies of families and twins have shown genetics to make substantial contributions to female sexual orientation, though environmental contributions are also important.

Because sexuality is an essential part of human life – for individuals and society – it is important to understand the development and expression of human sexual orientation. The goal of this study is to uncover genetic underpinnings of female sexual orientation, which has been studied less than in men, and thus ultimately increase our knowledge of biological mechanisms underlying sexual orientation. The study will achieve this goal by collecting and analyzing large samples to search for genetic markers associated with variation in the trait. This type of study is called a genomic-wide association study (GWAS). We have been funded by the National Institutes of Health (NIH) to conduct a five-year study of approximately 10,000 women recruited primarily from the United States.

Genetic contributions to male sexual orientation have been studied more widely than for women, and other research opportunities are available for men, including various previous studies conducted by our group. Our current research study focuses on women, who have been understudied in this area. We note that there is evidence from previous studies that there is some partial overlap in the genetics of male and female sexual orientation, but also evidence for significant separate contributions. Genetic influences are known to also be important for the development of female sexual orientation from previous family and twin studies.

This study involves two main components: a study questionnaire and a DNA sample.

The questionnaire takes approximately 30 minutes to complete. The questionnaire collects information on the following main areas: contact information, demographics, ancestry, sexual orientation, number of sexual partners, gender-related behaviors, romantic relationships, family relationships, personality characteristics, stress, mental health, height and weight, handedness (left, right, both), number of children, age when giving birth the first time, menarche, and menopause. Thus, the questionnaire collects a rich diversity of information about sexual orientation, as well as various other traits and conditions, in an effort to better understand the complexity of sexual orientation in women, far beyond just one or two questions about sexual interests, identity, or behavior. This will allow us to explore more hypotheses and to compare to previous and other ongoing research efforts.

Participants are then asked to provide a few milliliters of saliva (less than a teaspoon in volume), which we can obtain directly (if at a festival) or through the postal mail (if completing the questionnaire online). The saliva sample is used to extract DNA for the genetic part of the research study. The DNA will be studied to search for genes that might influence variation in female sexual orientation. Participants will receive a Starbucks $10 gift card upon completion of enrollment.

A full description of this study will be made available and discussed with potential participants as needed, before they agree to participate. This document is called the consent form. If interested, please click on “Enroll” to begin this process.

Saliva donation does not carry risks. Participants may possibly experience moments of psychological discomfort while completing the questionnaire, for example questions about childhood may prompt them to recall an unhappy time.

We have taken many safeguards to protect confidentiality of participants. Participants will not be personally identified in any reports from this study. The results from the analysis of DNA or other information from participants will not be released or shared in any way with insurance companies, or with any entity not directly involved in the research. No names or identifying information for participants will be published from this study.

As with other National Institutes of Health (NIH) studies, we have a Certificate of Confidentiality from the Federal Government (grants.nih.gov/policy/humansubjects/coc.htm) for this study. This certificate entitles us to protect all participants’ privacy (even from a subpoena).

Participants retain the right to withdraw from the study for any reason. Risks and protections are further described in the consent form.

Participants will receive a Starbucks $10 gift card upon completion of enrollment.

There are no direct therapeutic benefits for participants.

Participants are helping to improve scientific understanding of the development of and genetic contributions to sexual orientation.

Sexual orientation refers to erotic attraction and behavior between people. Sexual orientation manifests itself in a variety of ways: erotic attraction and behavior involving people of the same sex (gay or lesbian), different sex (straight), male and female (bisexual), or other variations such as queer, asexual, etc. Sexual orientation can also can refer to one’s sexual identity in a social sense (self-labelling), such as lesbian, bisexual, straight, etc.

Variation in sexual orientation occurs to some extent in every known human society, though its exact extent is a matter of debate. For women in the US, a similar proportion identify as lesbian as identify as bisexual, and most (typically 90%+) identify as straight. To increase the statistical power (ability to find differences that are present) for our analyses, we will “oversample” (vs. how common in the population) lesbian and bisexual women, compared to straight women (the latter being much more common). Thus, we aim to recruit roughly one-third in each group (lesbian, bisexual, and straight).

At the present time, there is no uniformly accepted theory of why some men and some women develop sexual attraction and behavior that is more or less focused on men, women, or both.

Most contemporary researchers believe that sexual orientation – the general disposition of people toward being gay, lesbian, bisexual, straight, etc. – is the result of both biological factors and psychological experiences. Most researchers do not believe that sexual orientation is the result of nature (biology, including genetics) alone or nurture (environment) alone. What researchers want to know is how specific factors in biology and psychology interact to guide sexual development. These researchers therefore look for differences between people of various sexual orientations.

Often studies are designed to show a correlation between sexual orientation and another trait (such as gender conformity). This is not the same as showing that such a trait causes sexual orientation, or vice versa. What is not yet known is whether these traits and sexual orientation have a common origin in genetics, or other biological or non-biological influences on development, though these hypotheses are being pursued. In any case, these lines of research are suggestive rather than definitive. Among other factors, it is these and other uncertainties that prompt continued research. We are positioning the current study to examine some of these relationships by collecting a rich diversity of information with the questionnaire about sexual orientation and also a number of other traits and conditions (including exposure to stress, stigma, discrimination, etc., which may mediate some of these associations).

We know from family studies that similarity in sexual orientation tends to cluster or run in families (i.e., with biological relatives). Aspects that could contribute to such similarity within families include, but are not limited to, genetics. Twin studies have consistently found that there is more similarity in sexual orientation in identical twin pairs (sharing all the same DNA variants) compared to same-sex fraternal (or sororal) twin pairs (who on average share half of the same inherited DNA variants, like other full siblings). These studies indicate that genetics is an important influence on variation in sexual orientation, but also that non-genetic contributions (often called the “environment”) must also be important.

While there have been more molecular genetic studies (such as linkage or association studies) on male than female sexual orientation, progress is beginning to be made with the latter as well. Most of the genome-wide association studies (GWAS) of female sexual orientation to-date, though large, have had limited information related to sexual orientation itself, often just one or two questions, sometimes limited to just behavior or identity. We aim to fill this gap with our current study by collecting substantial questionnaire information on a sizable number of participants, as a way to extend previous studies.

Of course, finding genes contributing to sexual orientation is only part of the story. It will also be important to figure out how genes actually influence sexual orientation. There will be many steps to be filled in to explain this process. The exact role of genes in sexual orientation is unknown at this point, and much more investigation will be required to clarify how influential they actually are in sexual development.

Researchers are interested in all aspects of human development, and sexual orientation is no exception. Sexuality, including sexual orientation, is a key element in human life and is of substantial interest to researchers and other people as well.

Not all this research may have direct practical benefits or effects. In other words, sometimes researchers study a topic to produce new information rather than new products or technologies. This is true of ‘basic research’ in general, and is true of the study of sexual orientation in particular. What is important in basic research such as this is that scientists add to existing knowledge about how human sexual development occurs.

Sexual orientation is central to many social debates (e.g., discrimination, marriage, military service, adoption) and should be informed by science. This is especially important for controversial areas with a high prevalence of distorted and hostile views. Nevertheless, the genetics (and more generally, causation) of sexual orientation remains understudied (especially for women), a situation that does not contribute to a rational, measured approach to societally important issues. We stress that our goals in these regards are to inform with scientific data.

In one sense, there is no difference in the study of male and female sexual orientation. The goal of research in both cases is to describe how people come to have the sexual interests they have and why they behave the way they do. Historically, researchers have focused more on male than on female sexual orientation.

Still, there seem to be some group differences between male and female sexual orientation. For example, some researchers have suggested that sexual orientation is more fluid in women than in men, meaning that sexual responsiveness may have more situation-dependent flexibility. Bisexuality appears to be more common with women than with men. To the extent that there are, in fact, differences in the development of sexual orientation in men compared to women, we have elected to mostly separately study male and female sexual orientation. While we initially focused on studies of men, the current study is focused on studying women. In addition, some aspects of our study will compare findings from women to those from men.

Some people believe that the biological study of sexual orientation will increase discrimination and prejudice against sexual minorities, such as lesbians and bisexuals. However, for example, some people seem more tolerant or accepting of sexual minorities if they believe that sexual orientation is something beyond a person’s ability to choose. Biological study might reinforce this view. Some researchers do not believe this is an important area of study. They think that the study of diseases, for example, is far more important than the study of sexuality. Scientists who study human sexuality do not accept these views. Sex researchers agree that the study of diseases is important. They also believe, however, that it is important to study human psychological development.

Research has already helped dispel myths about sexual orientation. Some researchers believe that factual information can help prevent distorted and hostile views. Because sexuality is an essential part of human life – for individuals and society – they believe it is important to devote some time and resources to studying human sexual development, with sexual orientation in general being part of that field.

Most researchers study sexual orientation in order to understand how people come to have the sexual interests they have. In other words, researchers are simply trying to explain why some people have sexual interest in men, in women, in specific sexual practices, and so on. The study of sexual orientation is one part of the scientific study of human sexual development. Therefore, most researchers do not study it in order to find ‘cures’ or ‘treatments,’ and that is certainly not our motivation. We further note that there is little evidence that the sexual orientation of adults is open to fundamental change. Sexual orientation in adults is deeply entrenched, no matter how it develops.

A very small and diminishing group of researchers believe that homosexuality involves mental disorder or dysfunctional psychological adaptation. Some of these researchers would like to find a method to prevent it or to eliminate it. The world’s leading professional organizations in psychiatry and psychology do not accept this fringe view as sound, and neither do we.

Some people think genetic studies of sexual orientation may offer more chance for therapies aimed at changing it. This is exceedingly unlikely. Physicians have no way to alter a person’s genetic endowment in order to change any complex trait having a genetic contribution. While there is considerable research in genetics in general, genetic treatments for sexual orientation are not in the foreseeable future and unlikely to ever be possible. It bears repeating that interventions like these are not the goals of this research project.

Some studies have specifically shown, for example, that gay men do not differ from straight men with regard to key psychological traits. Studies such as these actually helped lead people away from the view that being gay or lesbian was an illness or disorder. Various studies have shown that a large number of people engage in gay or lesbian behavior and this knowledge may have reduced the perception that sexual minorities represent an illness or disorder. Of course, it is impossible to predict exactly how the public will interpret and use scientific research. Still, the scientific study of a trait does not mean that the trait is an illness or disorder, and that applies here as well.

There is already a ‘test’ for sexual orientation: researchers (or anyone) can ask people what sexual fantasies and interests they have and how they behave sexually. They can also ask people how they label themselves: as gay, lesbian, bisexual, straight, or otherwise.

Some commentators are worried that researchers will find another kind of test, a biological test that would disclose one’s sexual orientation. It is unlikely that there could be a definitive biological test for sexual orientation. For one thing, no studies of gay men, bisexuals, or lesbians have ever shown that they have biological traits that are entirely distinct from everyone else. Instead, they share traits with everyone else.

When researchers find a genetic region (typically containing a number of genes) strongly associated with variation in sexual orientation, it remains highly unlikely that the genetic variation in this region would prove someone’s sexual interests one way or the other. For example, even while identical twins share all of the same genetic variants, their sexual orientation can be different; for example, one twin might be lesbian and the other might be straight. Sexual interests are complex and influenced by a variety of factors. Anyone can have sexual experiences with a man or a woman no matter what genes they carry. It is exceedingly unlikely that sexual orientation will be definitively linked to the presence or absence of a single, identifiable gene variant that can be disclosed through a test, or even a panel of such putative tests.

In short, it is highly unlikely that any biological (including genetic) test for sexual orientation will ever be able to come close to replacing the accuracy of simply asking people directly about their sexual interests and behavior. It is certainly not our goal to develop such a test.

Children of all orientations appear in all kinds of families, regardless of social status, economics, geography, race, ethnicity, religion, political beliefs, etc. However, some parents do not want to have gay, lesbian, or bisexual children because they disapprove. Some other parents may want to spare their children any difficulties growing up in societies that discriminate against sexual minorities. There are no known means that give parents control over the sexual orientation of their children. Genetic research is highly unlikely to change this situation and that is not our goal either.

Some commentators fear that hostility to gay men or lesbians might lead people to use genetic tools to produce ‘treatments’ for them. They also worry about the use of sexual orientation tests during pregnancy, in order to avoid pregnancies that might produce such a child. If there were therapies and tests of this kind, would they lead to fewer gay, lesbian, or bisexual people overall?

As a matter of well-established medical ethics and law, adults have the right to decline any and all unwanted therapies and tests. Most sexual minorities do not want to alter their sexual orientation. As a result, it is unlikely that a therapy – even if it existed – would significantly alter the total number of gay, lesbian, or bisexual people in the world.

If a prenatal test existed (see discussion above regarding the highly unlikely possibility of any genetic ‘test’ for sexual orientation), some prospective parents might use it, but its use would be in some ways limited. First of all, genetic testing of fetuses is complex, and it would be available only in developed countries. Most children in the world are born without any genetic tests, and there is no reason to think that this situation will change simply because researchers find some biological aspect to sexual orientation. It is also true that if there were some way to identify the likely sexual orientation of a child during pregnancy, some people might use that information to try and have gay or lesbian children. Testing might not be used only to avoid having gay, lesbian, or bisexual offspring.

It should be repeated that there is no biological therapy for sexual orientation and no prenatal test that can disclose a child’s likely sexual orientation, situations that are not likely to change. These concerns are matters of speculation.

While previous family and twin studies have shown that variation in female sexual orientation clusters or runs in families, and that much of that is due to genetics, there have been no linkage studies and very few association studies (i.e., molecular genetic studies such as the current study). A 2019 GWAS paper (pubmed.ncbi.nlm.nih.gov/31467194) makes a number of findings that are described in its public education website (geneticsexbehavior.info) in further detail, some of which are summarized below.

The study, entitled “Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior,” studied men and women separately and together. The study focused on the trait of same-sex sexual behavior, which was due to the large majority of the studied sample (from the UK Biobank) having limited questionnaire data (lifetime number of sexual partners, broken down into same sex and opposite sex partners).

Five genetic markers (locations of genetic variation) were found to be significantly associated with same-sex sexual behavior when two large samples (UK Biobank, and 23andMe) were analyzed together. Some of these markers were found in men, some in women, and some in both men and women. Each of the markers contributed a small amount to variation in the trait. This study further solidified the knowledge that a genetic ‘test’ for the trait was not feasible (it bears reemphasizing that developing such a ‘test’ was neither a goal of the authors, nor a goal of the current study).

This study also showed that different genetic variants influenced men’s and women’s sexual behavior, indicating that there is also utility in studying women separately (i.e., to find genetic variants relatively more important for influencing the trait in women). The complexity, variation, and multidimensionality of same-sex sexual behavior was highlighted. Genetic overlap was found between same-sex sexual behavior and some personality traits and other conditions (such as depression). However, such findings were difficult to interpret, in part due to a lack of information about the social environment (such as prejudice and discrimination) that might mediate the overlap (e.g., since such experiences could contribute to depression).

While our study will eventually include a large combined analysis portion (such as in the study highlighted above, with additional samples), we highlight here the aspects related to recruitment and study of a new sample of approximately 10,000 cisgender (i.e., women assigned at birth as female) women, aiming for about one-third each of lesbian, bisexual, and straight women. While not as large as biobank type studies (such as the UK Biobank, or the National Institutes of Health [NIH] All of Us Research Program), we are able to collect much more detailed information on our areas of focus: sexual orientation and related traits. This allows us to further pursue any genetic associations found in our or other studies, and to differentiate, for example, contributions from genetics versus social environment. Another difference is that we can enrich much more for sexual minorities (e.g., lesbians, bisexuals) compared to biobank type studies, which roughly reflect how common these groups are in their source populations. Our study will especially be able to explore for genetic overlap between aspects of sexual orientation and gender related behavior.