Zach Elliot is an author of two books on sex and gender and a producer of 20+ animated videos on sex differences. Here is the intro to his article: “What Are Sexes? There is much confusion in our current culture as to what sexes are and what they are not.”
There is much confusion in our current culture as to what sexes are and what they are not. When biologists make a claim about the number of sexes in a species, they are not making a claim about chromosomes, body types, or personal identity; rather, they are making a claim about the number of distinct reproductive strategies in that species.
A reproductive strategy is an evolved system for propagating genes and forming a new individual. In sexually reproducing species, producing a new individual requires the combination of at least two distinct and complementary reproductive strategies. These strategies are fulfilled through the delivery of genetic material in sex cells called gametes, which have half the genetic material of the parent. When two gametes fuse, they form a genetically unique individual with a full set of chromosomes.
Some species reproduce through gametes of the same size (isogamy) and can have many unique reproductive strategies called mating types, which control what gametes can fuse with one another, but their differences do not go far beyond the molecular level. On the other hand, most species in the plant and animal kingdoms reproduce through gametes of differing size and form (anisogamy), where there is an asymmetry in size and behavior between the interacting gametes and often the individual organisms themselves.
When gamete sizes are differentiated (anisogamy), there are typically exactly two sexes, no more and no less. In such systems, the reproductive strategy that produces the smaller gametes is designated as male and the reproductive strategy that produces the larger gametes is designated as female. It is not the physical size of the gametes themselves that differentiates the male and female reproductive strategies, but rather what those size differences represent.
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[Added December 2, 2022]
Zach Elliot discusses crocodiles and the fact that that there are only two sexes:
I had a discussion yesterday with an 18 year old male trans activist who thought atypical karyotypes like XXY were additional sexes.
By asking one simple question, I was able to change his mind.
Here’s how.“How do we know the sex of crocodiles?” I asked. “They don’t have sex chromosomes at all.”
With this question, I accomplished two things: 1) challenged his assumptions and 2) piqued his curiosity through an interesting example.
His response said it all
Heather Heying writes:
I appreciate your logical and well thought out examples and explanations. I am not a biologist. I am a mom of 2 boys and a girl sandwiched between. A week or so before my daughter had her third birthday, Lisa said, “When I have my birthday, I’m going to be a big boy like Robby.” Thinking she meant she would be older like her brother, I ignored it. But when she said the same thing a couple of times as birthday approached, I thought I should reassure her so I said, “When you were born and the doctor said, ‘We have a girl’ Daddy and I were SO happy! Now we had a boy and a girl, so when you have your birthday you’re not going to be a boy, you’re going to be our big gir….” That’s as far as I got. Lisa burst into loud sobs and covered her face! Days later she had a wonderful birthday and it never came up again.
I wonder what would have happened to that little girl if I’d suddenly begun calling her Luke or Limon and referring to her in male pronouns because somebody told me she was a boy in a girl’s body. Of course we wouldn’t have done that but there is so much nonsense surrounding “gender” today that I worry about these kids whose parents go along with momentary thoughts that come from childrens’ mouths. When a child expresses the desire to be the opposite sex, there’s a reason. It needs to be addressed and assurances given. In Lisa’s case, she loved and admired her big brother and now there was a new baby brother in the house. It wasn’t rocket science.
Octavia Sheepshanks writes this at “How I learned to stop worrying and criticise the magazine.”
More from Heather Heying, this time from her article, “A meander through dominance, gender norms, and mastery.”
Colin Wright, author of “Understanding the Sex Binary: Accurate, nonpoliticized descriptions of biology are essential to crafting policy to preserve the integrity of female-only spaces.”
When biologists claim that “sex is binary,” they mean something straightforward: there are only two sexes. This statement is true because an individual’s sex is defined by the type of gamete (sperm or ova) their primary reproductive organs (i.e., gonads) are organized, through development, to produce. Males have primary reproductive organs organized around the production of sperm; females, ova. Because there is no third gamete type, there are only two sexes that a person can be. Sex is therefore binary.
It is important to note here that the binary nature of sex is compatible with sex ambiguity because ambiguity with respect to sex is not itself a third sex. However, many gender activists falsely assert that the “sex binary” must mean something like “every human who has ever existed and will ever exist can be unambiguously categorized as either male or female.” Given this, they contend that providing examples of people with ambiguous sexual anatomy (i.e., “intersex” conditions) not only disproves the sex binary but also demonstrates that biological sex is a meaningless and even oppressive categorization scheme. (We will leave aside for now the fact that many of these same activists do recognize an alternative version of “biological sex” in the form of gender-identity bio-essentialism, or the theory that a person’s subjective self-conception of male or female is rooted in the brain itself.)
The chain of reasoning goes something like this. Sex is not binary because intersex people exist. Their existence demonstrates that biological sex is a spectrum. Since sex is a spectrum, that means no line can be perfectly drawn separating males from females. If no single line can be drawn, then anywhere someone chooses to draw one is totally arbitrary and subjective. If it’s totally arbitrary and subjective, then that means the categories male and female are also arbitrary and subjective “social constructs” with no firm root in biological reality. If that’s the case, why are we categorizing people in law according to these arbitrary labels instead of letting people simply label themselves? To do otherwise is to oppress people based on a biological falsehood.
This is just how the argument is made, and it is made with stunning success. Children in K-12 are regularly taught these days that sex and gender exist on a spectrum. Parts of the scientific establishment and the medical profession have also embraced this idea…
In both chromosomal and temperature-dependent sex determination systems, though an individual’s sex is mechanistically determined in different ways, it is always defined the same way—by the type of gamete his or her primary reproductive organs is organized around producing. This should be obvious, as it would have been impossible ever to have discovered these different sex-determining mechanisms without first knowing what males and females are apart from sex chromosomes and incubation temperatures.
These efforts by activists serve a single purpose—to portray sex as so incomprehensibly complex and multivariable that our traditional practice of classifying people as simply either male or female is grossly outdated and should be completely abandoned in favor of “gender identity.” This entails that males would not be barred from female sports, prisons, or any other space previously segregated according to our supposedly antiquated notions of “biological sex,” so long as they “identify” as female, whatever that means.