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A Scientific Discussion About Gender

Gender is considered a controversial topic even in psychology.

The topic of whether gender and sex are distinct from each other seems to grow in debate each day. During Pride month, the topic seemed to become more frequented and therefore might raise many questions.

A common argument against the distinction between sex/gender is that a female has XX as her sex chromosomes and a man has XY as his sex chromosomes. There can be points presented that perhaps the sex chromosomes aren’t exactly normal, like a woman only having one X or a man having XYY. However, let’s table this concept for now and focus on individuals who do not have an abnormal combination of sex chromosomes.

A depiction of sex chromosomes that do not address the largely unexplored effects of a non-binary sex chromosome set in a person’s karyotype — such as Klinefelter Syndrome (XXY).

A literature review paper composed by Arthur P. Arnold, Xuqi Chen, and Yuichiro Itol explain how individuals with the same sex chromosomes can still have varying degrees of genetic expression. Citing from several other sources, they compare genes to multiple networks working together in order to express a certain physical or behavioral trait, commonly referred to as a phenotype. As Arnold, Chen and Itol, point out, there can be some significant differences present simply from the individual having an XX or XY, such as males being more susceptible to red-green colorblindness. Because of this information, we can ask ourselves if someone’s XX or XY chromosomes are expressed in different ways or in different degrees based on their individual genome.

Different classifications of genders say “yes,” which many people might disagree with if they simply attended a basic biology lecture during their primary, middle or high school education. In the lit review, the authors proposed that four different classes of sex chromosomes exist. This itself is a very impactful claim to our discussion of the expression of a person’s biological sex — which we will label as gender for the remainder of the article in accordance to Arnold, Chen and Itol’s paper.

They note that several different studies note the existence of a single category of Y chromosomes, two categories of X chromosomes, and one category that involves specific regions of the sex chromosomes.

Class 1 are only known to affect males, as the gene that determines testis-formation, also known as Sry, are only present in these individuals. Class 2 consist of X chromosomes in a typical XX female that are both expressed. Class 3 are X chromosomes that are expressed at either a higher or lower level than Class 2. A proposed explanation for this is an abnormal genetic imprint as genes passed from the parent to the offspring. The authors propose that XY individuals can only have their single X chromosome imprinted from the maternal side, since they received the Y from their paternal side; however, XX individuals can have either or both of their XX chromosomes imprinted from either parent. Class 4 specifically seeks to understand the role of the non-coding regions of sex chromosomes, specifically heterochromatic genes.

A graphic depiction of the four classes of sex determining genes as per a 2011 study by Arthur P. Arnold.

Heterochromatic genes, used in this context, refer to as genes that comes in different varieties. For example, if there is a gene that regulates a person’s favorite color, it might be considered heterochromatic if the gene coded for specific shades of blue — such as navy, teal, or turquoise. Heterochromatic genes take the concept of alleles one step further; rather than saying a person has a gene that codes their favorite color to be blue, red or green, it could code for specific range of hues.

Evidence of heterochromatic genes are obvious in flies, or Drosophilia. Even though Drosophilia contain many more heterochromatic genes than mammals do, it’s possible that we could possess them.

Taking the discussion away from biology and towards a social standing, we could say that this could account for differences in personality regarding masculinity or femininity. If a normal XX female doesn’t necessarily like dresses or playing with children (activities traditionally thought to be female oriented), but instead enjoys playing sports or participating in a debate, does that disqualify her as a female or is she not considered feminine? Regarding her femininity, it might depend on the culture she lives in. It’s also very possible that she could like wearing dresses and playing sports, and liking one doesn’t automatically discredit the existence of the other activity. However, we don’t discredit the fact that she’s biologically a female because of her chromosomes.

The concept of nature versus nurture is also extremely relevant in the discussion about gender. If you raise a child with the perception that they will go to college and become a lawyer, a few outcomes are possible. The child can grow up and become a lawyer or can grow up and not become a lawyer. This analogy can be used to describe the way children who are raised with a certain personality expression in mind, but does it apply to children who aren’t raised with certain social expectations? If they know they’re able to have a career in whatever they want, they still might choose to become a lawyer. They also might choose to be a firefighter, an accountant, a welder, or a musician.

If this is the case, can the same method of thinking be applied to the expression of an individual’s “gender?”

This column* has a reputation for focusing on the strict neurobiology behind certain phenomenon; however, scientists must be able to admit when they’re unsure about something. The topic of gender identity can be a sensitive depending on the circumstances with which it is talked about. As time goes on, we continually learn more about the vast world around us as well as inside us. The things we knew in the scientific community twenty years ago does not compare to the number of things we know today — whether that be support for a claim or disproving an old scientific myth. The key to handling these situations is to stay open minded and curious, and not fall into the slippery slope that is confirmation bias.

*the Brain Rules column in the Daily Beacon
This article was originally published online at the Daily Beacon on July 3, 2017.



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Anu Kumar

Anu Kumar


I write about books, culture, behaviors, and practical self improvement. Head editor of