Colin Wright Discusses the Relevance of Binary Gonads to the Purported Sex Continuum

In an article at Quillette titled, “JK Rowling is Right—Sex Is Real and It Is Not a “Spectrum,” biologist Colin Wright discusses the importance of gonads to determining the sex of individual organisms in every species of animals except, apparently, human animals. Here is an excerpt:

Both of these arguments—the argument from intersex conditions and the argument from secondary sex organs/characteristics—follow from fundamental misunderstandings about the nature of biological sex, which is connected to the distinct type of gametes (sex cells) that an organism produces. As a broad concept, males are the sex that produce small gametes (sperm) and females produce large gametes (ova). There are no intermediate gametes, which is why there is no spectrum of sex. Biological sex in humans is a binary system.

It is crucial to note, however, that the sex of individuals within a species isn’t based on whether an individual can actually produce certain gametes at any given moment. Pre-pubertal males don’t produce sperm, and some infertile adults of both sexes never produce gametes due to various infertility issues. Yet it would be incorrect to say that these individuals do not have a discernible sex, as an individual’s biological sex corresponds to one of two distinct types of evolved reproductive anatomy (i.e. ovaries or testes) that develop for the production of sperm or ova, regardless of their past, present, or future functionality. In humans, and transgender and so-called “non-binary” people are no exception, this reproductive anatomy is unambiguously male or female over 99.98 percent of the time.

The binary distinction between ovaries and testes as the criterion determining an individual’s sex is not arbitrary, nor unique to humans. The evolutionary function of ovaries and testes is to produce either eggs or sperm, respectively, which must be combined for sexual reproduction to take place. If that didn’t happen, there would be no humans. While this knowledge may have been cutting edge science in the 1660s, it’s odd that we should suddenly treat it as controversial in 2020…. In humans, and transgender and so-called “non-binary” people are no exception, this reproductive anatomy is unambiguously male or female over 99.98 percent of the time….

By way of analogy: We flip a coin to randomize a binary decision because a coin has only two faces: heads and tails. But a coin also has an edge, and about one in 6,000 (0.0166 percent) throws (with a nickel) will land on it. This is roughly the same likelihood of being born with an intersex condition. Almost every coin flip will be either heads or tails, and those heads and tails do not come in degrees or mixtures. That’s because heads and tails are qualitatively different and mutually exclusive outcomes. The existence of edge cases does not change this fact. Heads and tails, despite the existence of the edge, remain discrete outcomes.

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Erich Vieth

Erich Vieth is an attorney focusing on civil rights (including First Amendment), consumer law litigation and appellate practice. At this website often writes about censorship, corporate news media corruption and cognitive science. He is also a working musician, artist and a writer, having founded Dangerous Intersection in 2006. Erich lives in St. Louis, Missouri with his two daughters.

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    Erich Vieth April 8, 2021 Reply

    From Endocrine Reviews, March 11, 2021.

    Biological Sex: The Definition of Male and Female
    Sex is a biological concept. Asexual reproduction (cloning) is routine in microorganisms and some plants, but most vertebrates and all mammals have 2 distinct sexes. Even single-cell organisms have “mating types” to facilitate sexual reproduction. Only cells belonging to different mating types can fuse together to reproduce sexually (2, 3). Sexual reproduction allows for exchange of genetic information and promotes genetic diversity. 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.

    In mammals, numerous sexual traits (gonads, genitalia, etc) that typically differ in males and females are tightly linked to each other because one characteristic leads to sex differences in other traits. The type of gonads is controlled by the presence of XX or XY chromosomes, and gonadal secretions in turn regulate formation of female or male reproductive tissues, and characteristics that differ in typical males or females. These characteristics include external genitalia, uterus and oviducts, sperm ducts, and secondary sexual characteristics such as facial hair and pitch of voice. However, many people cannot make either eggs or sperm, yet are recognized as female or male based on other physical characteristics; people who do not have either ovaries or testes are rare. For individuals that possess a combination of male- and female-typical characteristics, these clusters of traits are sufficient to classify most individuals as either biologically male or female. For example, a person with testes and a penis, who cannot make sperm, is usually classified as a biological male, as long as the person does not possess female features such as a vagina, ovaries, or uterus. Based on evidence presented, to define male and female individuals in general society, we expand the defining characteristics of sex to include nongonadal traits, as well as classical gonadal traits.

    A simple biological definition of male and female, satisfactory to all people, is elusive. In human societies, the terms female and male can have several meanings, as they refer both to a person’s biological sex and to their social roles. Most people learn to discriminate males and females from an early age, but often not based on biological traits (4). For example, behaviors such as pair-bonding, sexual activity, offspring defense and care, and mate/partner selection (5) involve complex interplay between sex steroid hormones and peptide hormones (oxytocin and arginine vasopressin); these behaviors are encouraged differently in women and men, which influences their role in the society and culture in which they live to behave as “females” or “males.” While these factors have little impact on their biological sex, they can have profoundly different outcomes in the behavior and health of an individual. Biological sex is dichotomous because of the different roles of each sex in reproduction. For scientific research, it is important to define biological sex and distinguish it from other meanings.

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