While we assume there are two large clusters of expression known as "male" and "female" directed by reproduction, there have been other genders from time immemorial. The Sumerian contains a creation myth where a goddess, Ninmah, fashions a being without sex organs, and tablets describe people who are outside of the normative of reproduction as having neither sex, or being "man-woman." Plato recounts a myth of creation that is similar, there are, originally, three genders.
For the moment, let me accept this division and survey some of the examples of creating a third gender. One is in language: many languages have Masculine, Feminine and Neuter genders, including Latin. However, in general we think of the third gender as a class of people.
One of these is the "eunuch," whether physically created, or by personal action. A monk for example, has renounced reproductive competition. This cluster of other gender exists for a variety of reasons. One is political. An example from early imperial Japan was caused by the heavy ceremonial duties imposed on the titular emperor. So, many emperors abdicated to be able to actually exert influence in a practice know as "cloistered rule," or Insei system.
If this sounds strange, realize that the Catholic Church has pursued official celibacy, and the Pope is a kind of cloistered ruler.
Physical eunuchs are one of the larger and more obvious regions of creating an additional gender. They have been created since written records, and perhaps before. They have been used, as the name implies, to protect and serve in circumstances where a male guard was desired, but one who was not capable of fathering children. In the court of Ming China, this form reached a kind of zenith. Located in Beijing, the "North Capital" to which the Ming dynasty relocated away from Nanjing, or the South Capital, the emperors constructed a vast palace and government complex known to westerners as "The Forbidden City."
In many cultures, where penetration defines masculinity, homosexual men adopt transgendered habits. They need not be physically castrated, though some are. What is more important is adopting a particular role. The long history of Hijra is an example of this kind of intersex space, in that they are men who take on the functions of women, and often the gender terms and clothing of women. They are refered to in Kama Sutra as "the third sex."
While the male as female is celebrated, it is known that many women have functioned as men, including Anna P.
Another category is from theatre, where in many cultures women are forbidden to act on stage. Shakespeare's theatre had no women, nor did classical hellenic drama, from which all Western theatre comes. In China Beijing Opera has only male actors. Men playing women become a third sex in the context of theatre, and in some cultures, in their private lives as well. Popular culture caught a glimpse of this Dan aspect in "Farewell My Concubine," written as a novel first by Pik Wah Li, or Lilian/Lillian Lee, and later brought to stage and screen.
The summary here is that there is a long standing recognition globally is societies that some individuals renounce behavior associated with "male" and "female" clusters, and this is often part of renouncing reproduction or other totemic roles. It is also associated with performing the sexual role without ties to reproduction, whether as a sacred prostitute, or as a male who has the receptive role in sex, particularly in cultures that define maleness by penetration.
This is associated with sexual orientation, political need, or personal expression, and as well with totemic significance of people outside of the male/female clusters.
The Nature of the Third Gender
From this we can see that while the normative cluster of male and female is very powerful, virtually every society has had times and places where people were not part of the normative clusters of male and female, and were allowed, or required, to express and live in a different group. This could be imposed, as Ming Eunuchs had to rise by entry into the class through castration, or it could be by some degree of choice.
The common threads are two. The first is the impulse behind the male/female normativity: reproduction, and behind this the desire to impose some regularity on inheriting, or patrilinearity, matrilineals need no such construct. There is a requirement then for sex and personal functioning outside of this area, and it is filled by a variety of individuals who, by renouncing reproduction as a motive, are granted particular places, and particular privileges in return.
However, reproduction is as much an excuse as a reason, and reproduction, ultimately, must be the reason for gender fluid individuals. The number of them suggests that there are evolutionary values for having gender fluid individuals as part of the population. It suggests that reproduction, while it is a driving force in normative gender roles, is also a Trojan Horse for that other part of normativity: getting what you want from people. Sex is not just about reproduction, but about the pleasure of sex, and the ego of sexual domination. Having targets ready to hand is as important a part of this as having breeding. Otherwise, VR sex rooms would not exist, because there is no breeding going on there, and men there have much higher percentage roles to reproducing. In fact, if a man really wants children, it is easier to get there than getting sex without responsibility is.
This is a topic I can write about with crystal authority: the purpose of sexual normativity for many of its devotees, is so that they can have a clear playing field to prove their masculine domination of being able to get free porn with tricks, traps, berating, and begging. The overwhelming strategy of men in such places is to demand normative information, and either repeatedly beg for sex, or to try and assert that the woman signed a contract to fall all over the first cock waved in her face, often sticking out of a pair of pants, by being there. I'll have more exact numbers on this in not too long. There's no reproduction, but there is a great deal of normative pressure.
As we know from biology, the competition for reproductive opportunities is intense, both within genders, and between them. The interests of the species, as a whole, is successful production of fit individuals, however individuals within the group have an incentive to cheat by making things worse for the species, but get more of their progeny. It is a wire. Too much, and the species, or group within it that carries their genetic material spirals the drain. Too little, and individuals won't get their genes into the next generation.
This brings me to the gender fluid.
The competition between men and women for advantage often centers around the resources invested. At a minimum a man invests the time to find a partner, and some small amount to inseminate her with his sperm. Then, he can be gone, and while the chance of a fit individual resulting is low, he can do this many more times than a man who helps rear the child, and has a higher chance of doing so than a man who reaches a pinnacle of worldly success that allows him to keep a harem, legal or allowed.
We all know of people who end up raising children from very short term affairs. So clearly, this form of reproductive strategy works well enough for the men who practice it to leave copies of themselves. But is it the only one that works? Are all men pump and dump, fuck and forget, stick and split, only waiting for the chance to do so?
I would argue not, consider the cycle of the currently labeled "secondary transgendered." The are often very successful as men, they breed. Then, as one anonymous essayist put it "the bell goes off." They tend to excel as men, they have children, then they transition. This is not unlike the classic cycle of a buddhist monk, or, for that matter, Franz Liszt, who had children, and then took on minor religious orders when this was over.
But that is an extreme, the norm is what drive the situation. Consider the man with some degree of gender fluidity. Theorists would call him queer, but that is also a normative label, to push people into a particular expression of fluidity. Let us take such a man as we find him. First, he has some behaviors, or some sympathies, which make him more able to understand, even mimic how women function. This is not to say he is not a guy, does not leave a trail of clothes around the house, and eats things that look and smell like road kill, but he is not in the category of men who are mystified by women's language, relational outlook, and so on. He talks more, and understands the need to talk. He may be more verbally skilled. He is capable of understanding, and thus has a higher chance of being able to raise children that he has to adulthood. He may or may not even identify this with femaleness. We are speaking, for the moment, strictly of gender fluidity.
Now how does this happen? The reality is from evolution is that fixed is unusual, variation normal. Consider the story I told in the first part: androgens are sent out to the body, and the parts of the body respond. But they don't respond equally. In extreme cases they do not respond at all. There is a natural variation in how much response, how much production, and where in the body there is response at all. Instead of calling men "male" in traits, we should say that they are "androgenized."
A man with differing sensitivities to androgens can be more male in some ways, because some parts of his body are not using androgens at the same rate. He has advantages in some kinds of reproduction. Since the same strategy does not always work, he will have better or worse chances depending on the time. Sometimes settling down works, sometimes it does not. Because he is a better care giver, and not dependent on chance, he has a higher chance of being able to breed with a woman who is sickly. This might seem a disadvantage, but it can be an advantage. He gets access to genes that the sower of wild oats does not have, and sickly could merely be a strong variation of something that is healthy if moderated, or in another circumstance. Allergies for example: too high an immune system might be bad where health is good, but good when health is bad.
These together show that some touch of gender fluidity in the variational pool is to be expected: it is a strategy.
The normal estimates of trans-gendered expression look at people willing to jump the very high hurdles to reassignment. Just the physical process looks terrifying: hormones, multiple surgeries, long rehabilitation to new gender. Then there is the psychological adjustment. On top of that the social adjustment. I'm not sure I've ever wanted anything as badly as the person who wants to fully transition must want it.
However, in VR, these do not exist. Gender choice is just that, choice. Anonymity makes maintaining that choice easier. And in SL, it is easier to equip a female. This leaves aside the man who is expressing something other than a desire to be female, in his choice of avatar.
However, some degree of fluidity, even if it is more in sympathy than reality, does not require anything more extreme than being willing to learn arts appreciated by women, accept roles and places that women value. In this the gender fluid male must include the submissive male, who is none the less as firmly attached to having a cock as can be, and the male who choses to present his male in a refined form. The male wearing a male avatar, but touching it with female taste, is a variation of a lighter degree, than the male wearing a female avatar. Both are less androgenized than the man walking around propositioning every woman he meets, but that does not mean they cannot find, and have, women.
As long as this is a stable strategy, that is, it offers benefits that offset it's costs, there is no reason it should not hold it's own place in the population. In smaller lighter degrees, it can even be seen as enough of an advantage.
What SL tells us is that men of these kinds are far more common than the analog world and analog normative clusters would predict. There are more men who fall outside the stripes of "male" than we would have thought. Some estimates say that 25% of all men who play SL have tried a female avatar. How many of them choose to do so regularly, or primarily, I do not know.
There is a long history of individuals, stories, and categories of behavior in human culture which do not fit into the bands of "male" and "female." These include eunuchs, men and women who renounce reproductive competition, feminine male homosexuals or dominant female homosexuals, actors in many ranges of cultures, and religious functionaries in many places. This long history is across cultures, though it's level of expression varies widely.
This long term history suggests that there is an evolutionary reason for a variation in alignment between physical gender, and the level of androgenization of behavior. The mechanism for this is an advantage in care based breeding over quantity based breeding.
Gender fluidity can express itself in a variety of ways, leading to a large estimate of men whose level of androgenization in behavior is much larger than the number who are transgendered. These would include men whose gender identity and expression are exclusively male. No mechanism for women is proposed here, but that does not indicate that there is not one.
VRs by allowing easier expression of gender fluidity, allow for men and women to use this easier expression both to be in some degree presenting an aspect of their gender identity which is otherwise forbidden, or to express other aspects of their personality which being the other gender helps. Such as being a man and being taken more seriously by male programmers.