What does it mean to be transgender?
There are several competing theories. Most commonly, it is said that transgender people have a ‘gender identity’ that differs from their ‘sex assigned at birth’. But what is sex assigned at birth? And what is gender identity?
Sex assigned at birth is (except in rare intersex cases) just a long-winded way of referring to sex. So, what is sex?
Note: This is a simplified discussion; a more detailed one can be found here:
All species reproduce. Some do this asexually. In that case, there is only one parent. The offspring are genetically (almost!) identical to the parent organism. Small differences are due to mutation.
The process of evolution works only because of differences between individuals of the same species. These differences mean that some individuals are better fitted to their environment than others. Those ‘fitter’ individuals tend to survive longer and produce more offspring.
As a result, species change over time, and on average the individuals within the species become better fitted to the environment.
In asexual species, evolution is very slow, because offspring are so similar to their parents. Mutation rates need to be low because most mutations lead to individuals who are less ‘fit’ than their parents. For this reason, many biological mechanisms exist to prevent or correct genetic mutations. This slow evolution means that asexual organisms cannot easily adapt to a rapidly changing environment. (I’m speaking here in evolutionary timescales, which are very long compared to the lifespan of an individual.)
Sexual reproduction is a solution to this problem of slow evolution. It creates genetic diversity without relying on mutation.
In sexual reproduction, there are two parents. They come together to produce offspring containing a combination of genetic material from both parents. The offspring inherit approximately 50% of their genetic material from each. Offspring are similar to both parents, but far from identical. Thus, there is far greater diversity among offspring. The system works in such a way that all (or most) of the offspring are viable.
Mutations also occur, but they play a relatively minor role in generating diversity. As in asexual reproduction, mutations usually cause trouble.
Organisms that reproduce sexually have a problem to solve. In order to reproduce, they need another individual of the same (or at least, compatible) species with which to combine genetic material.
Many sexually reproducing species come in two forms. Sexual reproduction then requires an individual of one form to ‘donate’ DNA to an individual of the other form; this second form ‘receives’ this DNA and combines it with its own to produce offspring.
The form whose reproductive biology is structured to donate DNA is called ‘male’. The form whose reproductive biology is structured to receive that DNA and produce the offspring is called ‘female’. (On this basis, the vast majority of individuals whose reproductive biology is non-functional can still be easily classified as male or female.)
The donated packet of DNA is called a ‘male gamete’. To produce offspring, this gamete must fuse with a ‘female gamete’ containing DNA from the female.
The male gamete is (typically) much smaller than the female gamete. This is because the male gamete needs to be more mobile than the female one. In many cases, the male gamete is not just mobile, but motile — i.e. self-propelling. Female gametes are larger, and non-motile.
When a species comes in two forms like this, it is described as ‘sexually dimorphic’. Many plants are sexually dimorphic, as are most animals. All mammals are sexually dimorphic. Human beings are mammals. Human beings are sexually dimorphic. So, humans come in two forms – male and female. There’s no third gamete, so in this sense (at least) there’s no third sex.
(Intersex people will be discussed later, but they too can be classified as male or female — based, as usual, on their reproductive biology.)
This classification based on what type of gametes an organism is structured to produce is what is meant when we talk about the ‘sex’ of an individual. Sometimes it’s called ‘reproductive sex’, or ‘sex class’ or ‘biological sex’.
Sometimes the seahorse is brought up as some kind of exception to the normal ‘rules’ of sexual dimorphism. It is pointed out that in seahorses, it is the male of the species that ‘gets pregnant’ and ‘gives birth’. The male seahorse has a pouch on his belly for carrying the eggs. When mating, the female deposits her eggs in this pouch. The male fertilises them, and the eggs develop to maturity in the pouch to emerge fully developed, but very small.
This is unusual — but it’s not an exception. How do we know it is the male seahorse that ‘gives birth’, and not the female? Because the one that ‘gives birth’ is also the one that makes the small gametes — ie. the male. Thus, in seahorses, we have a clear example that shows that the sex classification of an individual is based on the type of gametes produced, and beyond that, has nothing to do with how the species organises its reproductive affairs.
The Clownfish, the Parrotfish, the Barramundi, etc
Parrotfish, clownfish, and barramundi are what are called ‘sequential hermaphrodites’. For example, parrotfish have a lifecycle in which each individual starts off as female (‘the initial phase’) but later in life may change sex to become male (‘the terminal phase’).
So, how do we determine the sex of a parrotfish (or other sequential hermaphrodite)? Again, we look to see what type of gametes it produces — if it produces large gametes it’s female; if it produces small gametes, it’s male. The fact that the individual can change its sex doesn’t prevent us from determining which sex it is at any particular time.
But what about when a sequential hermaphrodite individual is in the process of changing its sex? Again this is simple — we look at the gametes. If we discover that the individual can currently produce no gametes, it is neuter — ie. it does not have a sex. If it can currently produce both, it is hermaphrodite — both male and female at the same time. If it produces small gametes only, it’s male; if large gametes only, female. There are no other possibilities. Again the sex of the individual is determined by the type of gametes produced.
Iain M. Bank’s Culture Novels
In the (fictional) Culture, humans are able to change sex in the manner of parrotfish. When they are male they produce sperm and may father children. When they are female they produce eggs, and can become pregnant.
These fictional humans are sequential hermaphrodites. And like the parrotfish, there is necessarily an ‘in-between’ phase while the individual is actively changing their sex. The change takes some time, and intuitively it seems obvious that say, during a change from male to female, they must start at a point of ‘maximum maleness’, and become gradually less male and more female over time, until finally they reach ‘maximum femaleness’.
But this is wrong — because at any point during this transition we could examine the individual and determine their sex based on their capacity for gamete production. Just as with the parrotfish, there are only four possibilities: male, female, neuter and hermaphrodite.
Even in high-concept science fiction, sex is not a spectrum.
Why do People say Sex is a Spectrum?
Here’s (part of) the entry on ‘sex’ from Julia Serano’s glossary of terms:
Sex: with regards to bodies, it refers to a suite of sexually dimorphic traits that may include chromosomes, gonads, external genitals, other reproductive organs, ratio of sex hormones, and secondary sex characteristics. In our society, these traits are classified in a dichotomous manner as either female or male, and people are assigned a legal sex on that basis. However, variability exists in all these traits, plus these traits may not all “align” (i.e., all male, or all female) within the same person — when this occurs, such traits (and the people who possess them) are often described as intersex.
Serano appears to be confused. The reason that “chromosomes, gonads, external genitals, other reproductive organs, ratio of sex hormones, and secondary sex characteristics” are “classified in a dichotomous manner as either female or male” is because all of these traits are highly correlated with an individual’s ability to produce either small or large gametes — ie. whether they are male or female.
What determines an organism’s sex is the organisation of its reproductive physiology — this is as true of humans as it is plants. Reproductive physiology is the only one of the “suite of sexually dimorphic traits” that actually determines the individual’s sex.
But females and males of many species can reliably identify each other (for mating purposes) without examining each other’s reproductive systems. How do they perform this astonishing feat? In effect, they ‘guess’ an individuals sex by looking out for the other sexually dimorphic traits — which are called ‘secondary sex characteristics’. These traits are often variable.
Imagine a human-like creature in which the male lactates, and is smaller, less muscular, and less hairy than the female. If we found such a creature, we would know it was the male form that lactates, because that ability would be found (almost exclusively) in the form that produces small gametes.
In this imaginary species we would expect females and males to identify each other in the same way that humans do; they would simply look out for the secondary sex characteristics of their own species. It wouldn’t strike them as strange that the male lactates, any more than it strikes the seahorse as strange that the male carries the young.
Now, if a female member of this imaginary species were to eat a certain fruit that caused her to grow breasts, lactate, lose all her hair, and even shrink, others of her tribe might misidentify her as a male, and treat her accordingly — but it would not in fact make her male. She would remain female, but with male secondary sex characteristics.
On the other hand, if this fruit were to cause her reproductive system to reorganise itself around the production of small gametes rather than large, she would become male — irrespective of size, hairiness, or ability to lactate. And she would still be male, even if her reproductive system — now reorganised around the production of small gametes — was non-functional. The tribe might choose to regard this individual simply as a female who’d been reshaped by a magical fruit — but their opinion would be irrelevant; she would in fact now be male.
What about intersex individuals, in which, as Serano puts it, the various “traits may not all “align” (i.e., all male, or all female) within the same person”?
Arguably, this is not so different from the case of the imaginary creature who ate the enchanted fruit. That individual ended up with sexually-dimorphic traits that were not all aligned; yet we were able to decide their sex on the basis of the underlying reproductive physiology.
We can do the same with human intersex individuals — and in almost every case, they can be classified as male or female, even if they happen to be infertile. There are many different intersex conditions, and each occurs only in either male or female humans — not both.
Nevertheless, intersex individuals can be taken as a special case, in that they are born with conditions that may cause ambiguity as to what sex they are. In some cases their sex may be assessed incorrectly, and / or they may suffer unnecessary surgical interventions.
Intersex people are frequently dragged into this argument, both by those who say sex is strictly binary, and those who insist sex is a spectrum. They often do not appreciate being used in this way.
Chromosomes, proteins and other bullshit
Another argument for the claim that sex is a spectrum is based on the complex biological mechanisms by which an undifferentiated ball of cells develops into a human being of one sex or another.
Here’s an infamous example, by ScienceVet:
Here’s another, by Rebecca R. Helm:
This argument normally mentions chromosomes, genes, and all kinds of chemicals and hormones with intimidating-sounding names. None of these are relevant — they are mentioned to convey the complexity of the process and to make the reader feel stupid for believing there are only two sexes.
It is true that the process is complex, and that many factors influence biological development. A number of unusual things can happen — some of which may result in a human being with an intersex condition.
There is a great deal of variation in secondary sex characteristics, and in the shape and size of reproductive organs. Individuals vary in size, colour, texture and amount of hair, penis length and girth, shape of the vulva, breast size and shape, facial bone structure, and so on.
But sex classification is not based on secondary sex characteristics; nor is it based on chromosomes, hormones, the size of reproductive organs, or on behaviour. It is based solely on reproductive capacity. We classify individuals this way across many different species. This captures an important commonality, that speaks of our kinship with the rest of the natural world.
In every sexually-reproducing species, there are two kinds of gamete — large and small. There are no intermediate gametes. Therefore, there are only four possibilities: an individual can be male, female, hermaphrodite, or neuter — no other possibilities exist. (In humans, there are no true hermaphrodites. A few may arguably be neuter — perhaps due to an intersex condition — but for them, sexual reproduction is impossible.)
The variation in human characteristics allows individuals to distinguish between possible mates, and choose whichever they prefer. Tastes vary widely; some male humans may prefer to reproduce with hairier females. Some female humans may prefer males with a smaller penis, or a squeaky voice. It doesn’t matter — all males are equally male; all females are equally female.
The argument that sex is a spectrum implies that some males are more male than others. Perhaps, according to this argument, the most male individuals would have the largest penises, the most hair, and the deepest voices; the most female ones might have the largest breasts, the widest hips, and the daintiest feet.
But this is not variability in sex itself (maleness versus femaleness), but in the secondary sex characteristics by which an individual signals its sex to other members of its species. These are biological aspects not of sex, but gender — what we call masculinity and femininity. They may be related to both ‘sexiness’ and ‘beauty’ — but they do not affect an individual’s sex.
Here’s a more detailed refutation, by Andy Lewis, of the ‘sex is a spectrum’ argument: