Work Text:
Dear Readers,
Since there have been several of you interested in how we structured our A/B/O universe, we decided to write a little paper to describe the world we created and the inherent biology therein. We both have biology backgrounds and have thought about this universe thoroughly (and probably far more extensively than we needed to, which probably comes from having backgrounds in research XD).
Also, just for the record, this document isn’t intended to shame anybody. We’re not saying that the A/B/O trope as it is now is “wrong” or “gross” or anything of the sort. One of us actually has a great love and fondness for the traditional, sticky A/B/O trope (and the other definitely still enjoys it too). This version just came about one day while we were talking about mixing science with fiction and if it was possible to explain A/B/O using biology and evolution. To our eternal chagrin and happiness, we think we found a way.
So, be prepared, because we’re about to use Shy’s anthropology minor in a very… unconventional way.
First off, some background information.
Evolution. A simple but heatedly debated term. It is most often described by the phrase “survival of the fittest” in common conversation. When people say this, they’re usually referring to how people who are stronger, richer, more athletic, better looking, etc. are more likely to survive hostile situations/succeed in life and are therefore “superior” in some fashion. This is called “Social Darwinism” and is taking a scientific concept and inaccurately applying it to social and political situations (Nichols, 2014).
Like most pieces of information bandied about by the public, this is wrong.
Evolution is entirely about reproduction, i.e. it promotes traits that allow an organism to survive until it makes a lot of babies. Life is just one big competition for reproductive success. It’s no good being bigger or more colorful if it gets you killed before you can reproduce. The word “fit,” in anthropology terms, means “best trait for that environment,” meaning that the species’ physiology is the better adaptation for surviving in that environment until they can reproduce (Nichols, 2014).
So, while being stronger, faster, or more athletic could be beneficial in surviving until reproduction in certain environments, it is not true of all environments. Sometimes being smaller, weaker, or less noticeable are actually the more advantageous traits.
Here’s a good definition: “[Darwin’s] basic idea was that changes come about in populations of organisms due to differences in the reproductive success of individuals based on their fit to a given environment” (Nichols, 2014).
Let us give an example of this process using skin color. Now, we’re not talking about “race,” as in the cultural concept. We’re talking about the level of melanin pigment in your skin cells that protects you from harmful UV sunlight. Now, most people assume that different shades of skin color, from light to dark, evolved to help protect against cancer. This, too, is wrong.
Cancer is best defined as a group of cells that grows without control in the body. Basically, a series of mutations overrides the cell’s apoptotic – or programmed cell death – pathway and causes the cells to replicate uncontrollably.
While UV sunlight can and will cause skin cancer, cancer usually develops much later in life, after the cells have had ample time to accumulate mutations, and well after a person’s peak reproductive age.
So, if skin cancer was not the driving force behind the evolution of different levels of melanin across populations, what is?
The current hypothesis is two-fold:
- The solar zenith angle is fairly low at the equator, meaning that UV radiation (UVR) has to pass through less atmosphere than at other latitudes before hitting the ground, which it does at relatively consistent levels. Now, UVR has three different wavelengths: UVA, UVB, and UVC. While UVC is mostly dispersed in the atmosphere, UVA has negative effects on DNA and the B-vitamin folate. Folate is degraded by UVA exposure and this folate deficiency, if it occurs during pregnancy, has been linked to neural tube defects (NTDs) in babies – which occurs when cell proliferation in the early nervous system is disrupted. Folate is also used in sperm production and there are studies being conducted to confirm whether or not folate deficiency plays a role in male infertility. Dark skin pigmentation most likely evolved to protect against birth defects and male infertility by shielding cells from harmful UVA radiation (Stinson, 2012; Langdon, 2005).
- At higher latitudes, less UVR reaches the ground because the sunlight passes through the atmosphere at an angle, so it has further to travel before it hits the ground and it does so at highly variable levels that change seasonally. We talked about UVA in the last point, but now it’s time to talk about UVB, which is necessary for the human body to produce vitamin D. Humans are incapable of producing our own vitamin D. We either need to consume it or have its production catalyzed by UVB. Vitamin D is used to maintain our skeleton, and vitamin D deficiency can lead to a highly disfiguring bone disease more commonly known as Rickets. People who suffer from Rickets have dental agenesis, weak muscles, and are bow-legged, which affects their ability to walk. All of these symptoms could have a negative effect on reproductive success. This is why people who live farther away from the equator evolved to have lighter skin: to allow more UVB to penetrate and produce vitamin D (Stinson, 2012). There was actually a very high incidence of Rickets during the Industrial Revolution at higher latitudes because the pollution practically blocked out the sun in cities. Rickets was, obviously, more common in people with darker skin who had immigrated to these areas, mostly because of the combination between lack of sun and more melanin. The U.S. government tried to mitigate this by adding vitamin D to milk (which doesn’t really help you if you’re lactose intolerant a.k.a. 70% of the world’s population… but we digress).
So, essentially, the higher the survival rate of the individuals with that beneficial mutation/trait/adaptation, the more they reproduce, and the higher the percentage of the population that has that mutation over time. Evolution is probably more aptly defined as descent with modification, where natural selection “selects for” beneficial traits (Nichols, 2014). The less efficient your survival method, the more likely you are to die before you can make babies that would carry on your genetics.
There is another common misconception about evolution: people think that it happens between and within individuals, but it doesn’t. The concept of evolution in individuals is actually similar to Lamarkism. This was a theory for species change proposed by Jean Baptiste Pierre Antoine de Monet, Chevalier de Lamark in the late 16 th to early 17 th centuries. He believed that an organism could control the forces and fluids in its body to interact with environmental challenges. For example, if a giraffe couldn’t reach the tree branches, it could will its neck to grow longer and, being such a marvelous adaptation, would then pass it on to its offspring (Nichols, 2014).
Now, Lamark was a key contributor to the development of evolutionary theory, but anyone who has ever tried to carry three things at once knows that Lamarkian evolution is patently untrue. No one, in the history of humanity, has spontaneously grown a third arm just because they really, really needed one. Evolutionary adaptations do not happen within an individual.
So, the traits that are “selected” for by evolution must be heritable. Here’s an example: Wolverine from X-Men. His genetic mutation is for super-healing, which makes him functionally immortal. If he had children, they could inherit this super-healing trait because it is genetic. However, they would not inherit his adamantium skeleton, because that is something that was done to Wolverine the individual and is not a heritable trait.
The main point is that evolution occurs over generations upon generations.
With us so far?
Now, let’s consider the ideas behind the Alpha/Beta/Omega dynamics universe. Pared down to the very basics, physiologically speaking, you have a person who looks exactly like a Regular Male on the outside, but can give birth; and you have someone who looks exactly like a Regular Female on the outside, but can impregnate others.
In this universe, we are ignoring the idea of Alpha males and Omega females. Women can already give birth, they don’t need any outside help from evolution. Men can already impregnate others, and they don’t need help either, so the evolution of Omega females and Alpha males doesn’t make biological sense. (For the purposes of this paper, sex = anatomical features, while gender = sexual orientation/partner preference/identity).
So, how and why would evolution select for traits that result in Omegas and Alphas?
There would need to be at least two factors at work:
- There would have to be some sort of pressure on reproduction, some long-term event or situation that made it hard for humans to reproduce.
- Camouflage was necessary.
For the increased pressure on reproduction to occur, the human population would have to have undergone a bottleneck event. That is, they must have been pushed to the brink of extinction. We know that sounds a bit extreme, but it has actually happened before in our past (Huff, 2009; Mirsky, 2010). This bottlenecking event must have been targeted towards one sex over the other, thus making camouflage of sex necessary.
Now, because this is Naruto, we have a great explanation on hand: demons. Canonically, demons lived alongside humans for many years and were a source of danger and fear, hunting and killing humans. If, for some reason, these demons preferred one sex over the other, and thus targeted them with more prejudice, then you can get an extreme decrease in population of one side of a breeding pair.
Basically, the human population has decreased sharply in number and the ability to reproduce and create more people is severely hampered by an extreme lack of one of the sexes required for reproduction.
The question “why would demons be targeting one sex of human over another?” is an intriguing one. They could see one sex as being more dangerous or, to get more realistic, one sex could be more delicious. Actually, the first thing that comes to mind is eggs. Think about fish. Fish eggs are used in dishes all the time, and they’re very sweet (caviar, roe, etc.). Other animals enjoy eating female fish that are full of eggs as well and, when fishing, some people throw the eggs back into the water after gutting the fish because other animals will eat them.
If human eggs were just as delicious to demons as fish eggs are to us… Well, there you have it. Yes, it’s disgusting to think about, especially since humans are used to being at the top of the food chain, but that’s the animal kingdom for you. (Think about what Dr. Wu said in Jurassic World: “To a canary, a cat is a monster. We’re just used to being the cat.”)
So, let’s assume for a moment that it’s the females that are being targeted by demons, so you have a dwindling population of humans that are mostly male. This is not good, this is the path to extinction.
Now, let’s talk about some biology.
At the beginning of development, all babies have both the Müllerian duct and the Wolffian duct, the systems that develop into the female and male reproductive organs respectively. During embryogenesis, these ducts are exposed to either testosterone or estrogen, depending on the baby’s genetics (their sex chromosomes: female - XX, or male - XY) and the appropriate duct develops while the other regresses (Widmaier, 2013).
So, if a mutation occurred in which neither duct regressed during development, you have an individual that has the potential to develop both reproductive systems – one meant for camouflage and the other actually being functional.
Now, it’s not as simple as that. All the hormones check and counter check each other and affect sexual differentiation in different ways. In real life, there are intersex individuals that have either atypical genetics (XXX, XO, XXY) or atypical hormone function (AIS, congenital adrenal hyperplasia, etc). These individuals usually lack the characteristic anatomical or functional sexual organs. This means that they are usually sterile or have limited fertility (Widmaier, 2013). (To be clear, we’re not discussing or delving into the psychological repercussions or gender dysphoria these individuals may face on a daily basis. We do not have first hand knowledge of what it is like to be intersex, nor are we making commentary about the experience. We are merely talking about the science behind it and no offense is meant.)
So, even though sterility is the usual outcome of mutation or alteration to the sex chromosomes, if the correct environmental stressors were present and the mutations acquired were just right… well, it’s a possibility. You could, in this case, most likely have a male individual that would look entirely male on the outside but be capable of getting pregnant and giving birth because he would also have the internal female reproductive organs. And, in a population where there is a much greater percentage of males, we feel it’s safe to assume that there would be a higher incidence of homosexuality, which would increase the chances of the first Omegas actually getting pregnant. Thus, the human population is rescued from extinction and the demons are highly confused.
To make the genetics as simple as possible, we’re going to use Mendelian genetics and Punnett squares (Klug, 2010). Let’s assume that the mutation that allows for individuals to be Omegas and Alphas is on the X chromosome (shown by the mutated sex chromosome looking like x instead of X). This allows us to assume that the first mutation produced an Omega, but because of the way the mutation works, this first Omega could then give birth to Omegas and Alphas as described below. Basically, the mutation only had to happen once and then it got passed down to both male and female offspring (instead of having an entirely new mutation just for Alphas).
When we show the genetics in a Punnett square it shows the probabilities of having male or female kids between the two parents. Below, we have a Regular Male (XY) on the left and a Regular Female (XX) on the top:
X X
X XX XX
Y XY XY
Based on these genetics, a Regular Male and Regular Female have a 50:50 chance of either having a Regular Female or a Regular Male kid. Now, if we insert the mutation... (let’s try it first between a Regular Male (XY) and an Omega (xY)):
x Y
X Xx XY
Y xY YY
So, a Regular Male and an Omega have a ⅓ chance of having an Alpha (Xx), a ⅓ chance of having an Omega (xY), and a ⅓ chance of having a Regular Male (XY). The YY combination would be lethal and the fetus wouldn’t develop (hence the math breakdown). They would also be incapable of having a Regular Female child. This means that Kouichi could either be an Omega like his mom, or a Regular Male like his dad.
Now let’s look at all the other procreosexual options! (Procreosexual being defined as a form of sexual attraction between sexes which are biologically capable of procreating. For example, a regular male or Alpha being attracted to a regular female or Omega. This is considered "straight" in this world.)
x Y
X Xx XY
x xx xY
An Alpha (Xx) and an Omega (xY) together has ⅓ chance of having an Alpha, ⅓ chance of having a Regular Male, and a ⅓ chance of having an Omega. In this verse, xx would be lethal and the fetus wouldn’t even develop. They would be incapable of having a Regular Female (XX) kid.
The only one left is an Alpha (Xx) and Regular Female (XX) pairing:
X X
X XX XX
x Xx Xx
They would only be capable of having either Alphas or Regular Females as offspring. Of course, there could still be neutrosexual pairings (between genders that cannot reproduce together i.e. MalexAlpha, OmegaxFemale, MalexMale, FemalexFemale, AlphaxAlpha, OmegaxOmega), but those relationships could not result in offspring so they’re not pictured here in Punnett squares.
Whew! That’s the genetics out of the way. Let’s talk about basic physiological differences next!
We’ll start with the scrotum, which houses the testes, which in turn produce sperm. The scrotum descends outside the body during development because ideal sperm production occurs at 2˚C lower than body temperature (Widmaier, 2013). Now, to maintain the outward camoflauge of being a Regular Female, Alphas can’t have a scrotum. The closest that we could figure was that an Alpha’s labia would be swollen in size – nothing too dramatic, but enough to allow for sperm production and storage. This wouldn’t be as efficient as having an actual scrotum, so the amount of viable sperm that an Alpha could produce would most likely be lower than that of a Regular Male. But, in this case, the need for camouflage is greater than virility.
Alphas also wouldn’t have an obvious penis. Our best theory would be that it developed and is stored in a “pouch” where the vagina would normally be. It stiffens and emerges erect when the Alpha is aroused, but remains hidden the rest of the time, maintaining the outward female façade.
In turn, Omegas most likely have a slower reproductive cycle – only menstruating around three times a year instead of once a month. It’s a compromise that needed to be made to allow for a reproductive system that doesn’t quite fit with outward appearance. Also, Omega males would still ejaculate during orgasm, they just wouldn’t produce any sperm. Considering ejaculate is only 5% sperm, there would be no noticeable difference during sex (Rehan, 1976).
For Omegas, there are two conceivable options. One: There is a vaginal opening between the scrotum and the anus, which honestly makes a bit more sense. Two: The vaginal opening is a part of the anus. Now stop for a moment before you start screaming at us. We don’t mean that the opening is up the anus, only that the vaginal opening is disguised with it. As in there’s a flap of skin and flesh that separates the vagina and anus, but from the outside, it looks like one orifice. However, the anal side works just like a regular anus – made for pushing things out and requires lube and stretching if penetration is desired. The vaginal side merely looks like the anal side from the outside, but it stretches easier and produces its own slick during arousal. Of course, having such a thin barrier between the systems would produce a lot of stress on the both of them, so this one is a bit more risky.
We’ll leave it up to the readers to decide which one they want to be the case because there will be a sex scene in our series, eventually, as well as an explicit birth scene. If more readers prefer one option over another, then we’ll do that one. Otherwise, we’ll just pick whichever one we think fits best.
Now: lactation. This is another area in which people can get a bit finicky when it comes to A/B/O and “over-feminization” of Omegas. However, logically and evolutionarily speaking, it wouldn’t make sense to allow for a mammalian sex to evolve that could give birth but be incapable of feeding the resulting baby. Given that humans are mammals, that means milk production. Breastfeeding has many beneficial factors. It transfers antibodies, white blood cells, and several proteins with antimicrobial effects to the baby to bolster its weak immune system; it slows down the reactivation of the menstrual cycle – giving the mother more time to recover after birth; and it is associated with lower risks for ear, respiratory, and GI-tract infections, sudden infant death syndrome, and other health issues (Stinson, 2012).
(Again, We’re not preaching to mothers about how they should feed their newborn babies. Sometimes there are good reasons why lactation may not be the best choice. We are simply talking about the evolutionary advantages for being physically capable of breastfeeding your child.)
Now, obviously Omegas can’t have breasts – that would undermine the whole camouflage thing again – but they’d have to have some mammary tissue in order to breastfeed. Perhaps just a small amount of tissue around the nipple until pregnancy, which is when mammary glands fully mature (Langdon, 2005). The Omega’s chest would probably swell towards the end of the pregnancy and they might develop very small breasts (easily concealed) in order to breastfeed their newborn children. These breasts could either recede after the child gets too old for breast feeding or just shrink a bit in size – still easily concealed with a thick shirt, vest, or binder if they’re very self-conscious.
The last physiological issue that we need to talk about is hip shape in Omegas. Humans suffer from what is known as the obstetric dilemma, which is basically the evolutionary compromise between bipedalism (the ability to walk upright, on two legs) and the fact that we have large brains. Basically, in order to support our torso while walking, the pelvis has to be narrow to a certain degree, but, since humans also have broad shoulders and big heads (to house our big brains), this makes birth… difficult. It’s much more painful and tiring for humans than for many other mammals and the baby has to actually rotate as it’s coming out in order to even fit through the pelvic opening. This is also why human babies are more helpless than many other mammalian newborns—they’re born earlier in their development so that they can still fit through the pelvic gap. As a result, human female hips are generally a bit wider than those of males in order to accommodate birth, but not so wide that it would compromise their ability to walk upright (Wiley, 2017; Trevathan, 2015). So, in this universe, Omegas would have female-like hips in order for them to realistically give birth.
Now, over time, as the demon threat decreased and the world became less chaotic and violent (most likely after the shinobi Villages started uniting), the incidence of Alphas and Omegas would most likely decrease. They would have been decreasing in civilian populations for a good deal longer than shinobi ones, just based on the sheer violence of the lifestyle, but an overall reduction in Omega and Alpha births has probably been observed over the past 100 or so years before our fics start.
However, shinobi clans would still have the highest incidence out of all remaining population groups. The Hatake are considered to have an abnormally low Alpha and Omega birth rate because they have long taken to hiding who was what from outsiders (even during the Clan wars) while no other shinobi clans, at least in Konoha, bothered to do the same. This is why the rest of Konoha believe that the Hatake incidence of Alpha and Omega births is even lower than that of civilians. In reality, their incidence was probably even higher than in the other Clans. However, all Hatake are smart and skilled in the shinobi arts, and almost incomprehensibly loyal – which led to a lot of them dying on the battlefield in service of their Village. That’s why the Clan has almost died out, despite having a higher than normal incidence of Alpha and Omega births.
Moving on to discuss some cultural consequences of having more than two sexes. We discussed it briefly in the author’s notes on Part 1 of this series, but we’ll go a bit more in depth here. The basic premise is that words that we consider to be more feminine or masculine (especially if they relate to reproduction), would not necessarily be the same in this world. For example: mother and father. In this case, we have it so that the person who gets pregnant and has the baby is called “mother” while the person who impregnates the other is the “father.” Though mother is feminine to us at first glance and father is masculine, in this world it simply denotes who gave birth in the relationship.
Now, if we move on to other words like “husband” and “wife” the vernacular gets a bit trickier. Since it’s not directly related to reproduction, you could have it one of two ways: “wife” being used only for people who can give birth and “husband” used for those capable of insemination. Therefore, Regular Males and Alphas would be husbands and Regular Females and Omegas would be wives. BUT, since there is a separation between marriage and giving birth (as they are not necessarily co-dependent), you can have it be more associated with the person’s gender instead of their sex -- a carryover from pre-Alpha and Omega times. Again, this is one of those things that would be personal preference both to the reader and to the character.
And, of course, you would have some transgender people in this world as well. This means that you will have individuals that go against “convention” when it comes to what they want to be called/what they identify as (he/she/they, mother/father/parent, husband/wife/spouse or partner, etc). It’s very dynamic, just like the real world. Since Obito and Kakashi are our introductory couple in this universe, we kept their sexuality and gender very simple: Obito is a procreosexual Regular male that identifies as ‘he’ and Kakashi is a procreosexual Omega that identifies as ‘he.’
This topic is so diverse and complex that it would require an entire other paper just to discuss the ramifications and all the potential genders/sexual orientations/etc that we’re just going to stop here.
Finally, a disclaimer. We are by no means experts in our fields and we have greatly simplified certain aspects of biology and evolution, both to make it easier to digest and because, if we didn’t, this “paper” could go on forever and might never reach a satisfactory conclusion. Because of this, there may be problems with our theory. If you find any obvious ones, please point them out! We’d love to expand upon this further with other people who may know more than us about this topic. If you are curious and want to read more about these things yourselves, we recommend all the articles and books in the works cited list and, if you want, we can supply you with a few more suggestions as well. Just comment below.
However, if you’re still unsure about A/B/O and all the fan-science and theories that go into it, keep in mind that this is Naruto. This is a world of demons and chakra and, most importantly, this is fanfiction.
Anything is possible if you just believe, especially in fanfiction.
Sincerely,
Shy & Tes
Works Cited
Huff, Chad D. et. al. “Mobile elements reveal small population size in the ancient ancestors of Homo sapiens.” Proceedings of the National Academy of Sciences of the United States of America, vol. 107, no. 5, 2009, http://www.pnas.org/content/107/5/2147.full#cited-by. Accessed on January 11, 2018.
Klug, William S. et. al. Essentials of Genetics. 7th ed. Pearson, 2010.
Langdon, John H. The Human Strategy: An Evolutionary Perspective on Human Anatomy. Oxford University Press, 2005.
Mirsky, Steve. “When Humans Almost Died Out; Earthy Exoplanets; And Scientific American’s 165th Birthday.” Podcast. Science Talk. Scientific American, 2010. Web. Accessed on January 11, 2018.
Nichols, Kimberly. Human Origins & Variation. McGraw-Hill Education, 2014.
Rehan, Naghma-E-Rehan E., et al. “The Semen Of Fertile Men: Statistical Analysis Of 1300 Men.” Obstetrical & Gynecological Survey, vol. 31, no. 1, 1976, pp. 52–55., doi:10.1097/00006254-197601000-00021.
Stinson, Sarah; Bogin, Barry; O’Rourke, Dennis. Human Biology: An Evolutionary and Biocultural Perspective. 2nd ed. John Wiley & Sons, Inc., 2012.
Wiley, Andrea S., Allen, John S. Medical Anthropology: A Biocultural Approach. 3rd ed. Oxford University Press, 2017.
Widmaier, Eric P.; Raff, Hershel; Strang, Kevin T. Vander’s Human Physiology: The Mechanisms of Body Function. 13th ed. McGraw-Hill Education, 2013.
Trevathan, W. “Primate pelvic anatomy and implications for birth.” Phil. Trans. R. Soc. 2015. B370: 20140065. http://dx.doi.org/10.1098/rstb.2014.0065 (If the link doesn’t work, try this one: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4305166/ We were able to click the PDF version on the upper right side and open it without having to sign in, so it should be free to the public)