An idea that has circulated recent identity politics is the reexamination of the gender binary. The arguments against this system include a proposed ‘gender spectrum,’ and with it, a lengthy set of ‘nonbinary’ genders to describe different areas within the spectrum. Different aspects of gender have also been differentiated and given their own spectra, including: gender identity, gender roles, gender expression, sexual orientation, sexual behavior, etc. Some of these hypotheses directly contradict current scientific understanding. Yet others, while not able to be disproven by science, have an approach that seems to remain ignorant of the mechanisms of biology and evolution entirely. To examine these claims more closely, an understanding of how the genders evolved in the first place can lay the groundwork for more applied reasoning.
Two prominent mechanisms of reproduction are known to exist: sexual and asexual. Asexual reproduction occurs in all prokaryotic organisms (nucleus-lacking and unicellular) as well as some plants and fungi. Sexual reproduction occurs in complex/multicellular plants, fungi, and animals. Since humans are animals and therefore reproduce sexually, it is more relevant to discuss sexual reproduction, but to put it briefly: asexual organisms reproduce using only the mechanisms within their body. Therefore, no exchange of genetic information with another organism takes place.
This exchange is important when juxtaposed with sexual reproduction, which does contain an exchange of genetic information. The exchange of DNA from 2 different organisms during sexual reproduction (known as genetic recombination) may be the reason behind the evolution of gender as a result of the adaptive power of genetic diversity. This recombination introduces genetic variability, which in turn introduces natural selection. The variability results from creating a new organism using a combination of genes (DNA segments that encode certain traits) from parents with unique sets of genes (genomes – overall genetic material). By introducing this variability in offspring genetics, sexual species have the potential to change their genomes across generations and give rise to anatomical differences that facilitate natural selection.
In the famous case of Darwin’s Galapagos finches, the finches developed differences in beak shapes. The reason the beaks changed over time is because the genetic recombination during sexual reproduction constantly introduced small changes to the genetics of the beak’s shape, and the finches with the beak most optimized for cracking nuts in it’s environment are the ones with the higher chance of surviving and reproducing – therefore passing on its optimized genetics to the next generation. The power of sexual reproduction displayed here, with Darwin’s finches, likely hints at the basis for the evolution of gender.
The case for the evolution of sexual reproduction (as opposed to asexual) is not set in stone, but the reason behind the binary nature of gender is clearer. It is mathematically inefficient to produce many different gametes (cells that carry reproductive capability), since it would require more and more sexual partners for the species to reproduce. But to introduce genetic variability, it is necessary to have more than one, so animals have two genders. Males have sperm gametes and are encoded using an XY chromosomal arrangement, while females have egg gametes and are encoded using an XX arrangement. Exploring the nature of chromosomes: an organism’s genome (DNA) arranges itself into chromosomes during cell division, which are tightly packed coils of DNA. Human genomes form 23 pairs of these chromosomes, the last of which is different between the genders. Females have 2 X chromosomes, but males have one X and a smaller Y chromosome. The differences of the 23rd chromosome pairs between the genders are the reason behind their anatomical differences.
In the context of evolution, a binary gender system offers a new mode of natural selection – sexual selection. This selection optimizes genes within a population based on the competition to reproduce. Organisms can compete between members of their own gender to seem more appealing to the opposite and can choose to mate with a member of the opposite sex that is most appealing to them. This force of competition drives more favorable genes to be more abundant in a population since those genes reproduce more often. One thing to remember when reasoning social evolution – genetic differences between the genders yield anatomical differences, which includes the anatomy of the brain. Just like the shape of a finch’s beak, the brain is a physical organ with its own genetics and is susceptible to the erosive effects of evolution. This means that the brain is also able to optimize reproductive potential by providing signals that indicate attractive mates – signals that have proven to be favorable and are evolutionarily advantageous.
Let’s take humans as an example: with a binary gender system, there is a reflected binary theme of facilitator/nurturer that permeates reproductive optimization. The human gametes (sperm & egg) express these traits: the sperm specializes in motility to arrive at the egg as quickly/safely as possible to deliver its genetic information, while the egg specializes in promoting the survival of the resultant zygote (result of sperm fertilizing egg) by becoming larger and storing nutrients. Their physical attributes match their assigned tasks as well: the sperm is small and nimble, but its size restricts it from carrying much aside from its genome. The egg, on the other hand, has the capacity to grow and store nutrients, since it does not need to move and therefore sacrifice size.
This theme is reflected in the differences between the genders on a macroscopic scale: males develop muscles and pain receptors while females develop womb mechanisms and breasts. These physical optimizations are important, but psychological evolution is extremely important as well. Females develop their affinity towards nurturing by being more keen to the health level of those around them – both mentally and physically. They are typically more devoted to maintaining relationships with people in order to have a support network for themselves and their children. They are also more receptive to the color of their fellow humans to check their health level – in fact – it is believed that this is the origin of females’ attraction to the color pink, since humans appear this color if they are healthy. Males mentally develop their affinity towards violence alongside their physical developments. Males who tend to fight more often accumulate experience in violence and therefore perform better in future bouts.
These differences between the genders are sexually selected for during evolution: females like males with muscles and males like females with ample breasts. Since males with muscles will prove to be more effective at survival, the females who view their genes as attractive will pass on those favorable genes to their offspring. Any females in that offspring will contain the gene that codes for a structure in the brain that would cause them to see muscles on males as attractive. Through this sexual selection, the two genders diverge in anatomy and psychology in order to optimize reproductive success.
Within greater societies, these differences in psychology manifest as gender roles. These roles are reflections of evolutionary differences that have existed to optimize reproduction. In modern societies, males have the role of making money and females have roles of taking care of children. These roles evolved naturally as packs turned into tribes, tribes turned into communities, and communities formed into societies. The basis for their formation are not only the physical differences that make each gender more effective at its assigned role, but also the psychological differences that make each role more fulfilling for each gender.
Males tend towards conflict, because their brains have evolved to reward them for participating in conflict. Females tend towards, compassion because of this same reason. In recent times, the identity politicians in question view these gender roles as completely independent from gender itself. The reality is that these roles only exist because of the social evolution downstream from physical evolution between the genders. As you can imagine, these roles are malleable and are by no means set in stone. However, pretending as though they are machinations designed to oppress the genders into fulfilling certain duties is incorrect.
Evolution has played out in a way that has created a binary system of gender within humans. Any social inventions like ‘gender identity,’ ‘gender expression,’ and the insistence of other genders are preemptive assumptions about personal philosophy. The human conscience is unquantifiably complex; creativity is a confusing umbrella term to define what makes us explore and interpret ideas in a unique way. Realizations and thoughts about self-identity can be profound and unorthodox, but they should not leave the confines of self-expression and venture into science or law. The science and reality of the situation is that gender is binary. There’s no spectrum. There are two. It doesn’t matter how pretty of a picture or how harmonious of an idea a spectrum of genders is; it is just not true. And we can take solace in the fact that we properly understand our place in the biosphere.