Same-Sex Behavior and Genetics

by Gayle Woloschak

This essay is part of a series stemming from the ongoing research project “Contemporary Eastern Orthodox Identity and the Challenges of Pluralism and Sexual Diversity in a Secular Age,” which is a joint venture by scholars from Fordham University’s Orthodox Christian Studies Center and the University of Exeter, funded by the British Council, Friends of the British Council, and the Henry Luce Foundation as part of the British Council’s “Bridging Voices” programme. In August 2019, 55 scholars gathered for an international conference at St Stephen’s House, Oxford. These essays are summaries of presentations given in preparation for the conference and during it. They together reflect the genuine diversity of opinion that was represented at the conference and testify to the need for further reflection and dialogue on these complex and controversial topics.

Human Genes

The Orthodox Church is generally not opposed to scientific knowledge and scientific endeavors. In fact, many early theologians and saints of the Church (including St. Basil and Ss. Cosmas and Damian) considered themselves to be scientists exploring nature and using nature’s pharmaceuticals to treat disease. When the Orthodox Church finds itself opposing science, it should take a clear look at both the present and tradition precedents and be certain that the stand it is taking is correct.

This is not to say that science dictates theology, rather that theology is open to consider all things in the world, including nature and how it is described. Scientists (like members of the Church) are obviously influenced by their culture, prejudices of their time, and false understandings. In the not-so-distant past, for example, scientists agreed that since women had smaller brains than men, they should not be allowed the same education, and that education must in some way adversely affect their reproductive abilities.[1]

The Church should consider all perspectives when taking a position on any issue. Of course, theology is paramount, but the science of the day should also be reviewed as contributing to how we understand our world.  As for other issues, so also for same-sex behaviors, on which topic psychologists, psychiatrists, and other physicians have weighed in. Recently, genetics has had the chance to contribute at least some new knowledge to the field of same-sex studies.

Twin studies and familial studies have demonstrated a genetic component to same-sex behavior, even though the exact factors that contribute have not been identified.[2] In past years, several reports had documented the identification of the “gay gene,” but none of these findings were repeated by other investigators, and “the gay gene” as a single gene involved in homosexuality was dismissed by the broad scientific community.

At the end of August 2019, Science published a paper by Ganna et al.[3] describing work done as part of a genome-wide association study (GWAS) of 477,522 individuals who had biobanked their DNA either in the UK or the US and given permission for this study. Of these individuals, 2-5% in the UK, and a larger sample from the US (that had used 23andMe), reported at least one same-sex encounter and were labeled as “non-heterosexuals” in the study (although the authors note that this is a problematic nomenclature). The purpose of the study then was to determine genetic variants associated with same-sex sexual behavior and to probe the biology and complexity of the trait.

GWAS is an observational study done to determine if any particular variant in genes is associated with a particular trait. GWAS projects investigate the entire genome as opposed to some studies that examine one or a few genes. While GWA studies can determine if there is a genetic association with particular traits, they cannot determine exactly which genes might be involved, because they use gene fragments rather than entire genes.

What did this study show? There were several key findings that influence how we consider same-sex sexual behavior:

(1) This study confirmed the work of familial and twin studies documenting that genetics plays a component in determination of same-sex sexual behavior. There are clearly other factors that are likely to be important, such as environment, but this study could not test for them.

(2) Same-sex sexual behavior is influenced by not one or even a few but many genes. The underlying genetic architecture of the trait is highly complex.

(3) The data support the model that many different genetic loci contribute to individual differences in predisposition to same-sex sexual behavior.

(4) Many of the loci with small effects are overlapping in male and female same-sex behavior and may contribute additively to the behavior.

(5) It is impossible from these results to either predict a particular behavior from one’s genetic make-up or to identify specific genes that might be associated with the behavior.

(6) In general, the work did not support the idea that the more someone is attracted to the same sex the less they are attracted to the opposite sex, as had been suggested by Kinsey. They suggest the need for the development of new tools for the evaluation of sexual orientation.

While specific genes could not be identified using these technique, five genetic variations were found to reach a very high significance. One set are associated with genes related to male-pattern baldness and another with olfaction. They both suggest a possible role for sex hormones in the process, since both sets of genes are hormonally influenced.

The authors have very clearly demarcated the limitations of their work and are careful to point out potential pitfalls in interpreting the study. As noted above, absolutely no predictions can be made about a person’s sexual orientation based on genetics, both because there are likely to be unknown non-genetic factors involved in the behavior and also because the genetic patterns are complex and mutli-genic. It can be stated only that there is a genetic component to same-sex sexual behavior; the study does not show the relative contribution of genetics or environment to the trait. These genetic features have not been shown to cause the behavior; they are merely associated with it and may play a role in its expression. As the authors note, much more work is needed in this field.

In short, this work confirms previous studies documenting genetic patterns associated with same-sex sexual behavior, adding to the literature a level of complexity that was not clear previously. As Orthodox Christians, we need to reflect upon how this new information about same-sex behavior influences our thinking. From the perspective of the Church, human beings are more than a package of genes and chemical reactions that occur, and we are more than our reproductive capacity and evolution. We do carry out the processes of DNA synthesis, replication of genes, and passing our genes on to offspring, through sexual reproduction. We have evolved and continue to evolve as part of our species. In fact, “those that evolve” is one of the definitions of life on Earth. But human beings contemplate, create, pray, build, and do so much more that partly depends on our biology but goes beyond it as well.

We need to consider, as Church, new questions that were not discussed until recently. In relation to sexuality, this will invite us to ask how far we should go in expecting people to ignore genetic inclinations? Are human beings just about evolution (reproduction is the only real driver of evolution) or are we also about relationship and communion? Have we articulated a theology to deal with same-sex behaviors? As in science, so in theology: there is much work to be done.


Sources Cited

[1] Hubbard, R. and Wald, E (1993) Exploding the gene myth. Boston: Beacon Press. This issue is also well-explored in Gabard, D. L. (1999) Journal of Homosexuality 37(1): 25-51.

[2] Pillard, R. D. and Bailey, J. M. Human sexual orientation has a heritable component. Human Biology (1998) 70: 347-365; Langstrom, N., Rahman, Q., E., Carlstrom, E., and Lichstenstein, P. Genetic and environmental effects on same-sex sexual behavior: A population study of twins in Sweden. Arch. Sex. Behav. (2010) 39: 75-80.

[3] Gamma, A., Verweij, K. J. H., Nivard, M. G., Mainer, R., Wedoe, R., Busch, A. S., Abdellaoui, A., Guo, S., Sathirapongsauti, J. F., 23andMe Research Team, Lichtenstein, P., Lundstrom, S., Langstrom, N., Auton, A., Harris, K. M., Beecham, G. W., Martin E. R., Sanders, A. R., Perry J. r. B., Neale, B. M. and Ziestsch, B. P. Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior. Science (2019) 365:  882, eaat7693. This original paper and an accompanying summary are available on these pages. Richard Swinburne’s contribution to the Fordham-Exeter Bridging Voices project also cites this study.


Gayle Woloschak, PhD, DMin is Professor of Radiation Oncology at Northwestern University School of Medicine and Adjunct Professor of Religion and Science at Lutheran School of Theology Chicago. 

Public Orthodoxy seeks to promote conversation by providing a forum for diverse perspectives on contemporary issues related to Orthodox Christianity. The positions expressed in this essay are solely the author’s and do not necessarily represent the views of the Fordham-Exeter project leaders, the conference as a whole, or the Orthodox Christian Studies Center.