“Biological Sex”: Is It Really So Clear-Cut?
🧬 We continue talking about that frightening and confusing term, “biological sex” — so confusing that even its advocates do not always understand it.
Have you read your Year 6 biology textbook yet?
Spoiler: it is not so clear-cut.
Contents
From the school textbook to chromosomes
If we open the school biology textbook that conservatives like to invoke, we will learn that living organisms can reproduce. There are many forms and processes of reproduction: spores, vegetative reproduction, mitosis, meiosis, and so on.
Humans reproduce sexually, a form of reproduction that involves two sex categories.
The sex characteristics necessary for the subsequent process of reproduction are genetically determined in the 23rd pair of chromosomes.
For most women, this is a pair of two X chromosomes; for most men, it is an X and a Y chromosome.
It is a pair of X chromosomes that appears in the logo of For Women Scotland, the organisation discussed in the previous article.
A long and complex process
The corresponding set of chromosomes in the 23rd pair — XX or XY — therefore initiates a long and complex process of sex development. It begins in the womb and only ends after puberty.
Most people with XX chromosomes develop sex characteristics conventionally considered female, while most people with XY chromosomes develop those conventionally considered male.
Primary and secondary sex characteristics develop under the influence of various hormones. These are the characteristics used to identify most people’s sex.
…Most?
Yes, most
By no means all women have XX chromosomes, and not all men have XY chromosomes. Nor does everyone have an XX or XY set in the 23rd chromosome pair.
Sometimes a person’s karyotype can differ from the familiar XX and XY.
Sometimes the body’s development can follow an atypical path and unfold differently. A person can have both male and female sex characteristics from birth.
Ultimately, sex characteristics cannot always be classified as exclusively male or female.
A diversity of traits and experiences
XXY, XYY, XO and XXX are all real chromosomal variations.
- Genitals may not correspond to the chromosome set.
- A person’s hormone profile may not correspond to their genitals.
- A person’s identity may not correspond to their hormone profile.
- Sex assigned at birth may not correspond to a person’s identity.
- Some sex characteristics — such as hormone profiles or secondary sex characteristics — can change over a lifetime.
Trying to establish universal categories for everyone is an example of black-and-white thinking. Appeals to “biological sex” are not, in fact, scientifically grounded.
Trying to establish universal categories for everyone ends up erasing the real human experiences of many people who do not fit into one of two categories.