As everyone knows, I adhere to the gametic definition of sex, in which individuals are classified as male or female (or, as in hermaphroditic plants, both sexes in one individual) based on whether their bodies are set up to produce small, mobile gametes (the “males”) or large, immobile gametes (the “females”). I’ve explained why I adhere to this definition, because it is not only universal in animals and vascular plants, but also because the difference between males and females in investment in gametes, which leads in general to females having a greater overall investment in reproduction, explains a lot of puzzles in evolution. One of them is why sexual selection creates males and females who are often so different in color, size, weaponry, and so on. Just remember: universality and utility.
Here’s a more formal definition given by Colin Wright write in his new post on his website, Reality’s Last Stand.
In biology, the definition of male and female has never been arbitrary or culturally relative. It is grounded in the concept of anisogamy: the existence of two distinct types of gametes—sperm and ova. This fundamental reproductive asymmetry defines the two sexes across all sexually reproducing anisogamous species. An individual that has the function to produce small, motile gametes (sperm) is male; one that has the function to produce large, immobile gametes (ova) is female. This is not a social construct or a philosophical preference—it is a basic principle of evolutionary biology, established long before today’s cultural debates.
Now of course this definition wasn’t pulled out of thin air: it is an a posteriori conclusion about how nature is set up. It is a truth that all animals and vascular plants have only two sexes, male and female, though in some species, as I said, individuals can be of both sexes. (And some individuals, like clownfish, can change their gametic sex.) But there is no third sex, no matter how hard the ideologues squeal about seahorses, clownfish, and hyenas. There is no third type of gamete in any species. In fact, the opposition to the binary nature of sex by gender ideologues have led some of them to argue that the gametic definition of sex is a recent confection sneakily devised by “transphobic” biologists who want to shoehorn all people (and animals and plants, apparently) into two categories. Colin wrote the piece below to show that this claim is false. The gametic definition has been around for about 140 years.
Click on the screenshot below to read the piece (Colin’s bolding).
Now I make no claim that the gametic definition of sex is universal among evolutionary biologists, much less all biologists. I haven’t taken a poll! But the biologists I’ve encountered in my own field almost universally adhere to that definition. At any rate, Colin goes way back in the past to show a passel of biologists (I know many of the more recent ones) who adhere to and have presented the gametic definition of sex. As Colin says:
The historical and scientific record is clear: from the 19th century to the present day, biologists, medical professionals, philosophers of science, and evolutionary theorists have used gamete type as the defining criterion for sex. This document compiles citations from that record, providing a reference point for students, scientists, educators, and anyone interested in understanding what “male” and “female” mean in biological terms.
These citations span more than a century of scientific literature, showing that the gamete-based definition of sex is not a recent invention or a reactionary response, but a longstanding, fundamental biological principle. While sex roles and secondary sex characteristics can vary, the definition of the sexes does not: male and female are reproductive categories rooted in the type of gamete an individual has the function to produce.
This document is a work in progress. If you are aware of additional scholarly references—especially historical ones—that clearly depict the gametic definition of sex, please share them in the comments so I can continue to expand and improve this resource. I encourage readers to bookmark this page and return to it often as a reference in conversations, research, and advocacy.]]
I think I sent him the Futuyma reference (not below), but I can’t remember. At any rate, you can read them all yourself, but I’ll put up five of them spaced apart, starting with the first one in 1888. These are from Colin’s piece:
1888 – Charles Sedgwick Minot. “Sex,” in A Reference Handbook of the Medical Sciences Embracing the Entire Range of Scientific and Practical Medicine and Allied Science, Vol. 6, Alfred H. Buck (ed.) (New York: William Wood and Company), 436-438
As evolution continued hermaphroditism was replaced by a new differentiation, in consequence of which the individuals of a species were, some, capable of producing ova only; others of producing spermatozoa only. Individuals of the former kind we call females, of the latter males, and they are said to have sex.
1929 – Horatio Hackett Newman. Outlines of General Zoölogy (New York, The Macmillan Company), p. 448.
Any individual, then, is sexual if it produces gametes—ova or spermatozoa, or their equivalents. Thus we would be justified in calling any individual that produces ova a female, and one that produces spermatozoa a male. One that produces both kinds of gametes is a male-female or, more technically, a HERMAPHRODITE. Thus we may say that the PRIMARY SEXUAL CHARACTERS of individuals are the ova or the spermatozoa, and that maleness or femaleness is determined by the possession of one or other of these two types of gametes.
A ringer: Simone de Beauvoir!
1949 – de Beauvoir, Simone. The Second Sex, translated by H.M. Parshley (New York: Vintage Books), 39
In the vast majority of species male and female individuals co-operate in reproduction. They are defined primarily as male and female by the gametes which they produce—sperms and eggs respectively.
2013 – Roughgarden, Joan. Evolution’s Rainbow: Diversity, Gender, and Sexuality in Nature and People. University of California Press. [Note: Roughgarden is a trans-identifying male]
To a biologist, “male” means making small gametes and “female” means making large gametes. Period! By definition, the smaller of the two gametes is called a sperm, and the larger an egg. Beyond gamete size, biologists don’t recognize any other universal difference between male and female.
2021 – Bhargava, Aditi, et al. “Considering sex as a biological variable in basic and clinical studies: an endocrine society scientific statement.” Endocrine Reviews 42.3: 219-258.
The classical biological definition of the 2 sexes is that females have ovaries and make larger female gametes (eggs), whereas males have testes and make smaller male gametes (sperm); the 2 gametes fertilize to form the zygote, which has the potential to become a new individual. The advantage of this simple definition is first that it can be applied universally to any species of sexually reproducing organism. Second, it is a bedrock concept of evolution, because selection of traits may differ in the 2 sexes. Thirdly, the definition can be extended to the ovaries and testes, and in this way the categories—female and male—can be applied also to individuals who have gonads but do not make gametes.
So much for those chowderheads who say that, using the gametic definition, neither a pre-puberty human, a postmenopausal woman, or a sterile person can be male or female. If you see this argument, you know you’re dealing with someone who’s intellectually dishonest.
Again, this is not a vote to see how many biologists (or feminists!) would define biological sex. It is meant, as Colin said, to show that the gametic definition of sex has been around for well over a hundred years.
Crystal clear, excellent.
Thank you Jerry, this is very informative and useful.
Yup.
Excellent and useful. Another thing we need (for research purposes) is analysis of how and why the genderist word salad that obfuscates the matter of sex definition got to be as widespread as it is. I’m unsure what kind of analysis would be most valuable here. An element of psychotherapy might be involved, but the primary method would have to be Anthropology, focused on the tribal rites and superstitions of Academia.
Colin is the O.G., a Jedi Knight of this genre. Seeing him light saber a collection of fools and motivated reasoners is beautiful.
His consort Christina Buttons is a top notch intellectual also.
D.A.
NYC
As for the gametic/gonadic definition of sex, here are additional quotations from the 19th century:
“Zu einem Manne ist ein für allemal das männliche Secretionsorgan, Hoden, zu einem Weibe Eierstock nothwendig.”
——————
“For a man, the male secretory organ, the testicle, is necessary; for a woman, the ovary is necessary.” [Google Translation from German]
(Müller, Johannes. Bildungsgeschichte der Genitalien. Düsseldorf: Arnz, 1830. S. 123 [§151])
“The different species of living beings are composed of two classes, which are essentially different from each other by their physical organizations: and these are the male and the female sex. This distinction of individuals of the same species arises from the difference of structure, function, and secretion of the parts destined for reproduction: the female contains in her ovaries the elements of the new beings, while the male is destined to vivify these principles with a fecundating fluid called sperm—spermatic fluid, in animals, and pollen in vegetables—without the action of which the female will find it impossible to produce a new being.”
(Virey, Julien-Joseph. “On the Generation of Animals and Plants.” The London Medical and Surgical Journal, Vol. VII. Edited by Michael Ryan. London, 1835. p. 812)
“Man nimmt gewöhnlich 3 Klassen Z. [Zwitter] an: männliche, geschlechtlose und weibliche. Das Dasein der Hoden oder Eierstöcke, als der wesentlichsten Organe, entscheidet darüber, welchem Geschlechte die Mißbildung angehört.”
——————
“There are usually three classes of h. [hermaphrodites]: male, asexual, and female. The presence of the testes or ovaries, as the most important organs, determines to which sex the malformation belongs.” [Google Translation from German]
(Neuestes Conversationslexikon für alle Stände, Achter Band: U–Z. Leipzig: Wiegand, 1838. S. 509)
“The existence in animals of generative organs of two kinds, and the necessity of the co-operation of both these organs in reproduction constitute the distinction of sex, or of male and female. In sexual reproduction both kinds of organ produce a substance essentially concerned in the process. The product of the female organ, or ovarium, as it is called, is the ovum or egg, a consistent organised body of a regular and determinate shape, in which the new animal is first formed and resides during its early growth. A whitish fluid is almost always the product of the male organ or testicle—termed semen, or the seminal fluid, from a belief formerly prevailing that it constituted, like the seed, the greater part of the new being.”
(The Cyclopaedia of Anatomy and Physiology, Vol. II: DIA–INS. Edited by Robert B. Todd. London: Sherwood, Gilbert, and Piper, 1839. p. 434)
“Die Fortpflanzung der Thiere ist an verschiedene Zeugungsstoffe – Ei und Samen – gebunden. Diese Stoffe werden bei den höher stehenden Thieren aber nicht von einem und demselben Individuum, sondern von 2 verschiedenen geliefert – das Ei vom weiblichen, der Samen vom männlichen –. Hierauf begründet sich der Unterschied der Geschlechter.”
——————
“Animal reproduction is dependent on different reproductive substances—egg and sperm. In higher animals, however, these substances are not supplied by one and the same individual, but by two different ones—the egg from the female, the sperm from the male. This is the basis for the difference between the sexes.” [Google Translation from German]
(Leisering, A. G. T. Atlas der Anatomie des Pferdes und der übrigen Hausthiere. Leipzig: Teubner, 1861. S. 62)
“Das getrenntgeschlechtliche Individuum mit Ovum, ohne Sperma, wird allgemein als weibliches (femininum), das nichtzwittrige Individuum mit Sperma, ohne Ovum, als männliches (masculinum) bezeichnet.”
—
“The separate-sex individual with ovum, but without sperm, is generally called female (femininum), the non-hermaphroditic individual with sperm, but without ovum, is generally called male (masculinum).” [Google Translation from German]
(Haeckel, Ernst. Generelle Morphologie der Organismen. Zweiter Band: Allgemeine Entwickelungsgeschichte der Organismen. Berlin: G. Reimer, 1866. S. 61)
“Wenn auch die Differenzierung der Keimdrüse nicht immer den Typus des übrigen Geschlechtsapparats bestimmt, so stellt sie doch das eigentlich geschlechtsbestimmende Moment dar …”
——————
“Even if the differentiation of the gonad does not always determine the type of the rest of the sexual apparatus, it is nevertheless the actual sex-determining factor, …” [Google Translation from German (slightly improved by myself)]
(Klebs, Edwin. Handbuch der pathologischen Anatomie. 1. Band, 2. Abtheilung. Berlin: A. Hirschwald, 1876. S. 723)
“The essential attribute of the male sex is the generation of spermatozoa, that of the female the generation of ova, accomplished in the one case by a testis or a homologous organ, and in the other by an ovary or a homologous organ.”
(“Sex” in The Century Dictionary: An Encyclopedic Lexicon of the English Language; Vol. 5. Edited by William Dwight Whitney. New York: The Century Co., 1890. p. 5535)
“The reproductive organs may, anatomically, vary in position, size, and shape in different plants and animals, but the being is a male when in possession of male gametes or sperms, a female when in possession of female gametes or ova, neutral when both kinds of cells are absent or not developed, and hermaphrodite or monecious when both are present in the same individual.”
(Baerecke, Vida Z. “Letter to the Editor (August 17th, 1897).” In The American Journal of Obstetrics and Diseases of Women and Children, Vol. XXXVI: July–December 1897. Edited by Brooks H. Wells. New York: William Wood & Co., 1897. p. 359)
Fellow skeptic Michael Shermer has been tweeting about this form of applied epistemology in sport. In this instance the “piste” part is especially apt.
https://x.com/michaelshermer/status/1907803870597886199
Good stuff!
You bet it is. I hope more women will do the same.
Valuable information, clearly stated, thank you. Bookmarked for future quotes!
In any case, suppose it comes to pass that the language still changes so that the accepted meaning of the terms sex/male/female is that these are mere social constructs. We would then have to invent new words for the evolved biological state of those who produce eggs and those who produce sperm. These terms are essential for accurate communication, research, education, and medical practice. But those new words would still be usurped by the social climbers, who would grab them up while looking around to make sure that everybody sees how good and virtuous they are.
I think the new term you require, redundant as it may seem, may be “biological sex.” It was much easier when sex had to do with biology and gender had to do with language.
Yes… but even that is abused. I do use that term now in my classes, and then say that it’s just ‘sex’ for short. So I budged a little. I don’t mind it, but I get into convolutions about the terminology and so far I have not felt pressure to.
Why not small and large? (But I’m a medium!)
Restrooms: small and large
Sports: small and large
Clothes: Do you have that in a small large?
“Biological sex” is redundant. Yes, I use it all the time.
First rate.
I’ve already gotten into a little trouble with a few friends over this.
I like: “So much for those chowderheads…”. Much more polite than my: “You’ve got it ass-backwards…” to a friend who should know better, but who fits J.K. Rowling’s characterization: “Non-trans-identified leftybros (displaying) their own impeccably progressive credentials”.
Has anyone seen (or read) this yet? This is a new book published by the Princeton University Press (hence reputable?).
Sex Is a Spectrum: The Biological Limits of the Binary : Why human biology is far more expansive than the simple categories of female and male by Agustín Fuentes.
The thesis is: “Why human biology is far more expansive than the simple categories of female and male”.
“A fascinating must-read for anyone interested in the science of human sex and gender.”—Lucy Cooke, author of Bitch: On the Female of the Species
I disagree with the premise of human exceptionalism which is implicit in the statement “human biology”.
Any hypothesis that is not broadly applicable across species is less useful than the prevailing gamete based definition.
And I have yet to see any alternate idea define how one weighs the various aspects that influence where a human falls on such a spectrum (Dr Novella not withstanding). Any book worth the time ought to provide clarity and objective criteria.
Colin’s post is very informative and it’s a resource that I’ll check from time to time.
However, for the trans ideologists this only proves that transphobia dates back to the 19th Century.
I doubt these historical quotes will convince the dogmatic minded. In any case, they’ll think they are proven right. That’s how the religious mind operates.
In modern times the most important paper on the evolution of anisogamy [ sperm and eggs] is Parker, Baker and Smith, 1972. While Colin Wright cites a few more recent Parker papers, he omits Geoff Parker’s own historical overview… of his 1972 paper, and his 1970 paper on sperm competition, the extension of sexual selection theory to gametes themselves. His paper is free and open access…it is here.
https://www.mdpi.com/2073-4409/10/2/287
Its list of references is itself a major historical record on thinking about anisogamy and sperm competition over the last half century.
I’ve read much of what you’ve written on this topic and understand the biological definition of male and female; I’ve read Colin Wright and Zachary Elliott’s writing as well. I understand there are exactly two sexes, and that throughout most eukaryotes an individual organism can be male, female, both, or neither. I understand that individuals humans with DSDs can actually be classified as male or female.
But I’ve come to think that it’s also irrelevant to any of the policy debates going on right now: 46XY-CAIS individuals are biologically male but there is absolutely no realm of public policy in which they should be treated as anything but female. They should use women’s restrooms, women’s locker rooms, and be allowed to compete in women’s sports.
The Paradox Institute sex development charts make it clear that these individuals are biologically male: they have internal testes, and no ovaries or uterus (https://www.theparadoxinstitute.com/read/sex-development-charts?gallery=3172116646539824925976&item=66b18f88dd68d210e74617c6). The Paradox Institute also has a long article with IMHO convoluted reasoning which does state that 46XY-CAIS individuals are biologically male, but defines a whole new category of sex rejection. (https://www.theparadoxinstitute.com/read/the-case-of-cais-understanding-the-complexity-of-sex-reversal) Which is to say, they have to throw away the straightforward biological definition and come up with a human- (or mammal-?) specific exception in order for the scheme to make sense for “medical and practical purposes.”
And if that’s the point we’re at, we could very well just start over when defining policy for “practical purposes.” Which would be in my preference: restroom access by presentation; spaces of communal nudity by some combination of presentation and external genetalia; women’s sports by lack of androgenizing adolescence.
An interesting and informative article. Thank you Jerry.