Last updated on: 7/11/2018 | Author:

Is It Relevant to Look at the Animal Kingdom to Determine if Human Same-Sex Behavior is “Natural”?

General Reference (not clearly pro or con)

Tina Adler, freelance science writer, stated in a Jan. 4, 1997 Science News article titled “Animals’ Fancies: Why Members of Some Species Prefer Their Own Sex”:

“Research into the benefits and origins of homosexuality in animals is important to the furthering understanding of animal behavior. However, people can’t help wondering what the findings say about, well, people. Growing numbers of human studies are now linking homosexuality to unique biological traits.

While some researchers examine what benefits animals may derive from same-sex sexual activities, others are trying to pinpoint straightforward biological causes of the behavior.”

Jan. 4, 1997

[Editor’s Note: For a list of animals that exhibit homosexual or transgender activity, please see our “Gay” Animals resource.]

PRO (yes)


Robin Dunbar, PhD, Professor of Evolutionary Psychology at the University of Liverpool, England, was quoted in the July 23, 2004 National Geographic article titled “Homosexual Activity Among Animals Stirs Debate”:

“The bottom line is that anything that happens in other primates, and particularly apes, is likely to have strong evolutionary continuity with what happens in humans.”

July 23, 2004


Paul Vasey, PhD, Associate Professor at the University of Lethbridge, and Volker Sommer, PhD, Professor at University College London, explained in the introduction to their 2006 book Homosexual Behaviour in Animals: An Evolutionary Perspective:

“Because we are committed to a broad comparative perspective on the topic of homosexual activity, this volume also includes a chapter on the human ‘animal’. It is our conviction that evolutionary treatises should not be ‘homocentric’ in that they either focus on humans, while excluding a comparison with other animals, or that they focus on animals, while excluding our species, Homo sapiens. Such boundaries, when maintained for reasons of orthodoxy and dogmatism, are meaningless and counterproductive to scientific understanding – a point which we will reiterate below. Of course, humans are unique and the behaviour of humans does, therefore, require unique explanations – but so does the behaviour of bottlenose dolphins and bisons.”



Bruce Bagemihl, PhD, biologist and researcher/writer, stated in his 1999 book Biological Exuberance, Animal Homosexuality and Natural Diversity:

“[H]omosexuality in any given context (or species) can be seen as the intersection at various points on a number of… axis, thereby allowing comparisons to be made across multiple factors…

[T]he plurality of homosexualities in both animals and people suggests a blurring of the seemingly opposite categories of nature and culture, or biology and society… such diversity may in fact be part of our biological endowment, an inherent capacity for ‘sexual plasticity’ that is shared with many other species.

On the other hand, it is equally meaningful to speak of the ‘culture’ of homosexuality in animals, since the extent and range of variation that is found (between individuals or populations or species) exceeds that provided by genetic programming and begins to enter the realm of individual habits, learned behaviors, and even community-wide ‘traditions.'”


CON (no)


Erik Holland, writer and author of The Nature of Homosexuality published in 2004, stated in his book:

“The best evidence so far suggests that same-sex sexual behavior is uncommon in the animal kingdom.

Depending on the species, same-sex sexual behavior could possibly be related to dominant-subordinate relationships, regulations of social tension, alliance formation, seeking a partner to help take care of one’s offspring, undermining the conceptive-reproductive success of non-relatives, or could simply just be non-adaptive behavior that exists for the sole purpose of satisfying sexual desires in those experiencing same-sex attraction.”



Luiz Sergio Solimeo, a member of the American Society for the Defense of Tradition, Family and Property (TFP), wrote in the article titled “The Animal Homosexuality Myth,” from the National Association for Research & Therapy of Homosexuality’s website (accessed Feb. 13, 2007):

“If seemingly ‘homosexual’ acts among animals are in accordance with animal nature, then parental killing of offspring and intra-species devouring are also in accordance with animal nature. Bringing man into the equation complicates things further. Are we to conclude that filicide and cannibalism are according to human nature?…

The animal kingdom is no place for man to seek a blueprint for human morality… The fact that man has a body and sensitive life in common with animals does not mean he is strictly an animal. Nor does it mean that he is a half-animal. Man’s rationality pervades the wholeness of his nature so that his sensations, instincts and impulses are not purely animal but have that seal of rationality which characterizes them as human.

Thus, man is characterized not by what he has in common with animals, but by what differentiates him from them. This differentiation is fundamental, not accidental. Man is a rational animal. Man’s rationality is what makes human nature unique and fundamentally distinct from animal nature.”

Feb. 13, 2007


Charles Socarides, MD, Founder of the National Association for Research and Therapy of Homosexuality (NARTH), stated in a 1995 letter to the New York Review of Books:

“Firstly, the term homosexuality should be limited to the human species, for in animals the investigator can ascertain only motor behavior. As soon as he interprets the animal’s motivation he is applying human psychodynamics — a risky, if not foolhardy scientific approach.

Secondly, assumptions as to the origin of human homosexuality cannot be based on the study of genes, hypothalamus, anterior commissure, or the lower brain structures, or species such as the drosophila fly, or even lower primates; because in man the enormous evolutionary development of the cerebral cortex has made motivation — both conscious and unconscious — of overwhelming central significance in sexual patterning and sexual-object choice. Below the level of chimpanzee, sexual arousal patterns are completely automatic and reflexive.”