October 16, 2023 | Jerry Bergman

Flawed Research Underlies Gender Confusion

 From two sexes to sixty genders in only a few decades.
Are they inborn? New research reeks of speculation.


by Jerry Bergman, PhD

A new analysis by José M. Gómez et al., in an attempt to explain several of the so-called “sexual orientations”, opined that these behaviors evolved, thus are inborn. Gómez et al., writes “Same-sex sexual behaviour probably evolved independently several times in mammals as a way to smooth out social relationships when they started living in groups.”[1] The real question that must be asked is, are transvestism, nonbinary, asexual, agender, bigender, genderfluid, demisexual, graysexual, homosexual, aromantic, questioning, intersex, and the 47 other claimed sexual orientations genetic? The evolutionary problem for many of these behaviors is that

Same-sex sexual behaviour has attracted the attention of many scientists working in disparate areas, from sociology and psychology to behavioural and evolutionary biology. [but because]… it does not contribute directly to reproduction, same-sex sexual behaviour is considered an evolutionary conundrum.[2]

An analysis of the work of Gómez et al. documents that evolutionary claims of sexual behavior are largely speculation. Zimmer noted that one “analysis of more than 6,000 mammalian species found that about 4% exhibited same-sex behaviors — including courtship, mating and forming long-term bonds — and these were particularly prevalent in non-human primate species.” Since only four percent of the 6,000 mammalian species exhibited these behaviors, 96 percent (5,760 mammal species) do not exhibit these behaviors.[3] Many of these so-called same-sex behaviors are not sexual in the way humans think of homosexual relationships.

Most readers are familiar with the “sexual” behavior of dogs, most of which is not sexual in terms of reproduction, but related to dominance and, for many other reasons, including forming long-term bonds (this exists in many other mammals besides dogs). As any dog lover knows, dogs form long-term bonds with cats and other animals as well, an observation confirmed by functional MRI.[4] When their companion dies they openly miss their friend. Even the term “courtship” is a vague, undefined term that may not relate to human courtship when discussing animals. Recognizing this, José Gómez, the lead author of the new study, an evolutionary biologist at the Experimental Station in Almería, Spain,

cautioned that the study, published ….  in the journal Nature Communications, could not shed much light on sexual orientation in humans. “The type of same-sex sexual behavior we have used in our analysis is so different from that observed in humans that our study is unable to provide an explanation for its expression today.”[5]

Furthermore, the new research replaced one speculation with another:

Some researchers have proposed that this behavior has existed since the dawn of the animal kingdom. But the authors of a new study of thousands of mammalian species paint a different picture, arguing that same-sex sexual behavior evolved when mammals started living in social groups. Although the behavior does not produce offspring to carry on the animals’ genes, it could offer other evolutionary advantages, such as smoothing over conflicts.[6]

The main problem with all this speculation is the incorrect assumption that sexual orientation in humans is genetic and has evolved. However, the research is absolutely clear: Sexual orientation is the result of early experiences.[7] One of the largest studies, involving 477,522 individuals from the United Kingdom and the United States, and a replication analyses of 15,142 individuals from the United States and Sweden, determined that no evidence exists for a genetic cause of homosexuality.[8] These aggregate genetic influences partly overlapped with those that influence a variety of other traits, including smoking, cannabis use, risk-taking, and the personality trait “openness to experience” such as fast driving, mountain climbing, and taking drugs. All genetic variants accounted for only 8 to 25% of the variation in same-sex sexual behavior.

Research Methodology

Previous studies of same-sex sexual behavior typically have involved observations of a single species, or a small group. In contrast, Dr. Gómez and his colleagues looked for evolutionary patterns. They

surveyed the 6,649 species of living mammals that arose from reptilelike ancestors starting roughly 250 million years ago. Looking over the scientific literature, they noted which of them had been seen carrying out same-sex sexual behaviors — defined as anything from courtships and mating to forming long-term bonds.[9]

Use of “courtship” behavioral indicators are especially problematic because many animals exhibit behaviors we define as courtship, including ritualized movement (“dances”), vocalizations, mechanical sound production, or displays of beauty and strength, that are not related to sex.[10] Mammalian societies form hierarchies in which top-ranking animals display behavior that some define as courtship behaviors. However, an analysis of the claimed evolutionary tree revealed that animals which engage in same-sex sexual behavior tended to be social species instead of solitary ones, supporting the idea that so-called “courting behavior” was social behavior having nothing to do with sex. Same-sex behavior might be one way mammals can manage their social world by forming bonds and alliances with other animals, or to divert aggression. Another problem is that

Males and females were about equally likely to be observed carrying out same-sex sexual behavior …  In some species, only one sex did. But in still others — including cheetahs and white-tailed deer — both males and females engaged in same-sex sexual behavior. The researchers then investigated how the behavior arose in mammals. Looking at an evolutionary tree, they found that species engaging in it were scattered across the tree’s branches, suggesting that the behavior independently arose in each lineage.[11]

Gómez and colleagues added that “the earliest members of major living mammal groups, such as primates, probably didn’t engage in same-sex sexual behavior. As new lineages evolved, some of them started exhibiting the behavior.”

Zimmer admits the problems with the Gómez study, and quotes Dieter Lukas, evolutionary biologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, who opined “Taken together, the findings in this study have not convinced me that there is a single explanation for the occurrence of same-sex behavior.”[12] Dr. Zuk and Jon Richardson, a postdoctoral researcher in her lab, put forward a different explanation for same-sex behavior. They observed that

Same-sex sexual behaviour (SSB) occurs in many animals and is often treated as an anomaly requiring special explanation. One common explanation for SSB is mistaken identity…. such as attempting to mate with immature individuals or inanimate objects. …[it may be useful to use] an alternative approach to thinking about SSB by instead considering an individual’s mating filter. A broad filter means directing courtship toward anything that resembles a potential mate, whilst a narrow filter means only courting with receptive targets…. many other species may engage in same-sex sexual behavior as part of a strategy to take advantage of as many opportunities to mate as possible.[13]

Dr. Zuk likened the strategy to a smoke detector: “You want a smoke detector that is sensitive enough to detect all fires… And if it does that, occasionally it’s going to go off when you burn your toast.”[14]


Research such as that done by Gómez and his colleagues, although touted as proving some politically correct belief, when analyzed, often does not hold up under scrutiny. Much behavior displayed by mammals that is claimed or implied to be sexual is likely not sexual. Nor is there any evidence that this behavior ever evolved. These attempts to negate the Bible’s simple teaching that the first two humans were Adam and Eve, and that there are only two genders, fail and cause enormous problems when they attempt to prove something very different.


[1] Grahm, Flora. Daily briefing: Mammals probably evolved same-sex sexual behaviour several times; https://www.nature.com/articles/d41586-023-03185-1#:~:text=Same%2Dsex%20sexual%20behaviour%20probably,they%20started%20living%20in%20groups. emphasis added.

[2] Gomez, Jose et al. The evolution of same-sex sexual behaviour in mammals. Nature Communications. 14(5719) 2023. https://www.nature.com/articles/s41467-023-41290-x.

[3] Zimmer, Carl. Same-sex behavior evolved in many mammals to reduce conflict, study suggests; https://www.nytimes.com/2023/10/03/science/same-sex-behavior-evolution-mammals.html?unlocked_article, 2023.

[4] Berns, Gregory. Functional MRI in Awake Unrestrained Dogs. PLoS ONE. 7(5):1-27. e38027.

[5] Zimmer, 2023.

[6]   Zimmer, Carl. Same-sex behavior evolved in many mammals to reduce conflict, study suggests; https://www.nytimes.com/2023/10/03/science/same-sex-behavior-evolution-mammals.html?unlocked_article, 2023.

[7] Bergman, Jerry. Massive study finds no evidence of a gay gene; https://crev.info/2019/09/massive-study-finds-no-evidence-of-a-gay-gene.

[8]  A. Ganna, K.J.H. Verweij, M.G. Nivard, R. Maier, R. Wedow, A.S. Busch, A. Abdellaoui, S. Guo, J.F. Sathirapongsasuti. 23andMe Research Team, P. Lichtenstein, S. Lundström, N. Långström, A. Auton, K.M. Harris, G.W. Beecham, E.R. Martin, A.R. Sanders, J.R.B. Perry, B.M. Neale, B.P. Zietsch, Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior. Science 365(6456):eaat7693, 30 August 2019.

[9] Zimmer, 2023.

[10] Sommer, Volker, and Paul Vasey. Homosexual Behaviour in Animals: An Evolutionary Perspective. Cambridge University Press, New York, NY, 2011.

[11] Zimmer, 2023.

[12] Quoted in Zimmer, 2023.

[13] Richardson, Jon, and Marlene Zuk.  Rethinking same-sex sexual behaviour: Male field crickets have broad mating filters; https://doi.org/10.1098/rspb.2023.0002, 26 April 2023.

[14] Richardson and Zuk, 2023.

Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,800 college libraries in 27 countries. So far over 80,000 copies of the 60 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.

(Visited 267 times, 1 visits today)

Leave a Reply