Chapter Text
In order to write an effective AU like this one, it's necessary to ask a lot of 'why's. Since many readers of Changeling asked to see my answers to those whys, here are a few of them.
First of all: Why would men EVER need to get pregnant and bear children when biologically, the human female is so much more ideally suited to that task?
In this world, the Jotun invasion happened far earlier in Human history than in movie canon. And also, instead of a raiding force, as was demonstrated in the movie Thor, the Jotuns sent an occupying force with intent not to take back the resources of Midgard, but to remain there and take the whole place. Their approach to this was slightly more efficient than the early Mediterranean and later European cultures though; instead of bothering to enslave the natives, they went straight to a plan of two-or-three-generation genocide. They bypassed human warriors (such as they were in the Stone Age,) and focused their attentions on finding and killing human females.
The reason for this difference in policy is that Laufey is of the caste of Jotun who never assumes a shape that can carry children, however Skadi, the King at the time of this invasion was a mother, and understood the vulnerability of a culture whose childbearers come under direct threat. (As stated in the story, Jotuns do not have a male and a female gender, but rather are fully hermaphroditic, and capable of either impregnating, or becoming pregnant, depending on their will.)
Ergo Skadi ordered raid after raid on different human populations on all the continents of Midgard, doing massive damage to the numbers of women and girls there. In some later cases, Jotuns began to assume human shape to undermine the remaining human resistances, and it was at this point that Asgard intervened. But the damage to humanity was done. The human female population had dropped well below species-critical numbers. (At its lowest, perhaps 5% of all humans were female.)
When the Jotun invasion was stopped, and its armies driven back to Jotunheim, Freya learned what had been done on Midgard, and decided it merited retribution from her. She cursed all those Jotuns who has assumed the form of human females to remain that way, and to life out their lives as such, forgetting that they had every been anything else. Their shapeshifter nature meant that they lived normal human lifespans, and then died, still under the Asgardian Queen's curse, but they were prolific while they lived, and within two generations, their half-human children had mutated to take up the childbearing slack.
Because this occurred during the Stone Age rather than the Bronze or Iron ages, there was no written record of it, or of humanity ever having less than four genders. There are some songs among the Australian Aboriginal tribes, and there are some pictograms that would reflect the difference if anthropologists knew what they were looking for and at, but to the people of this world, four genders is just what it means to be human.
So explain this Omega thing please. How does it work?
(Okay, here is where you skip if talk of butts and the stuff that comes out of them. You have been warned.)
An omega male is born with a vestigial womb in his lower intestines. When he is a child, it is little more than a bump, like a tiny, densely muscled diverticule off his small intestine. When he reaches puberty, depending on his health, his diet, and certain environmental factors, it will either develop further, producing an omega male who, under the right conditions and with the right stimulus, can conceive and carry a child, or else it will atrophy, and produce a null male who will not reproduce at all unless he gets very lucky and manages to be father a child on a woman. (This is not an access problem, as null males make extremely stable, safe mates for women – it's actually a hormonal problem, since omega males do not produce a lot of testosterone at the best of times, and null males don't produce much more.)
When a healthy omega comes to puberty in a safe environment, with plenty of food, and a pack around him providing the sense of stability he craves, the demi-womb will stabilize into a permanent organ over the first year of puberty. After that, he will experience a heat every month, but it is not necessarily a fertile heat, it is really more of a mate-drawing heat. The omega's system sacrificed the ability to make certain less-necessary, but still valuable hormones in favor of being able to carry the infant to term, and so these heats induce alphas, who produce more of the missing hormones than THEY need, to sort of... share the wealth. This is how the presence of omegas in the human genome gave rise to the presence of alphas – mates with more of the hormones they needed got more access to omegas, and thus were able to pass on those genes to further generations.
Under normal, healthy conditions, an omega who has had repeated sexual contact with one alpha over the course of several months, will be triggered into a fertile, breeding heat a couple of times a year. This happens when the presence of a consistent chemical signature tells the omega's system that the odds for a safe, protected pregnancy are high. Over the course of three months or so, the demi-womb will grow to about the size of a fist.
Omegas have about three to five feet less small intestine than other males do, in order to make room for the potential baby – because of this, they are much pickier about food, and have very good scenting capabilities in order to be sure they don't poison themselves with spoiled goods. Omegas have, consistently, the most sensitive, discerning noses of any humans. Part of this is due to the need to be able to analyze their food, but another part of this is down to their need to correctly assess the status, mental state, and mood of the humans around them. Being pregnant makes you automatically more vulnerable to all kinds of violence and neglect, so being able to predict and avoid it was just something they needed to be able to do, and the scenting ability was the quickest way to manifest that. Omegas are better at tracking, and at social manipulations because of this, so it's only a small logical step from that to understand how they would become the anchored center of almost all pack structures.
Here's how the breeding heat progresses for an omega male.
* A few days before the pheromones become detectable to other individuals, the omega will essentially stop eating. This is in order to clear fecal matter from the lower intestine and colon. In order to maintain energy and hydration during this time, omegas begin to crave high calorie, high fat liquids and semisolids. (A side note -- lactose and sugar sensitivities are very rare in omegas because of this particular dietary quirk.)
* As the heat ramps up, guardian muscles above the colon and the demi-womb/diverticule lock down, making defecation actually impossible. If the omega eats solid food -- most particularly high-fiber food -- during this time, they tend to throw it right back up again. This is one of the many reasons why omegas have a greater scent-discernment and analysis capability than other rankings do. Their noses are hardwired to their stomachs so they know what's safe for them to eat and when.
* Once the guardian muscles clamp down, the walls of the colon begin to secrete an antibacterial, hormone laden substance not unlike a human male's precome. For obvious reasons, digestive bacteria in the reproductive organs is Not A Good Thing. It's at this stage that the heat scent becomes detectable to others -- enticing, but not compelling as of yet. This is good, because the effect of this secretion is similar to a low-level fever, and most omegas are NOT interested in sex when they've got achy joints, a slight headache, and some cramping going on.
* The fever breaks after three to five hours, depending on the length of the fast before it, and the omega at that point begins to feel, and hormonally project the strong urge to mate. Depending on the omega's chemical state (how long it's been since he's been sexually exposed to alpha hormones, how much emotional and environmental stress he's under, the presence or absence of strong threats of violence or disease in his environment, time elapsed since his last breeding heat -- all are factors here,) his heat will last anywhere from 12 hours to 5 days.
* Once a heat breaks, the omega will generally want to sleep for a full 24 hours. This is to facilitate conception, presuming the omega is in fertile phase at the time of his heat. During this time, his hormonal output tends to induce strong protective instincts not only in the alpha he's been with, but in any betae and other omegas near him. In high-tension, high-risk situations (such as a duress-breeding -- where an alpha exploits the heat-state to get sex from an omega who has otherwise rejected him -- fully as socially and legally disallowed as any other kind of rape, but in this society it's a hair-split difference, because it can ONLY happen to males) the omega will not sleep at all afterward, for obvious reasons. It is generally presumed that it's during the post-heat sleep that conception happens if at all, however this is a myth that has been soundly disproven in the modern century.
A non-fertile heat is similar to this in events, but is less extreme in terms of how long it goes on, and how painful it will be for the omega if he cannot or will not get access to alpha hormones. Essentially, think of this as an extreme form of addiction detox for the omega; survivable, but hell on earth while it's going on.
In Changeling, the reason Steve triggered into a full on breeding heat without prior access or exposure to an alpha, was because of a) the super serum making his breeding process terrifyingly efficient once it was given the chance to omega up on him, and b) because he triggered himself. All his gear that he had with him when he went down was stuff he'd had in the combat field – it smelled strongly of his alpha self. However one thing the serum couldn't do was activate both sets of the glands he carries at once. So once he'd been in omega phase long enough to trigger off himself, it was not going to go back into the box until it had finished its process dammit. He went through a physical process that takes most omegas three months, in three weeks. And people wondered why he was cranky and shy and in a freaked-out headspace – PMS ain't nothin' on this, kids.
A pregnancy for an omega is actually quite dangerous. The chance of organ rupture is very high given the arrangement of the internal structures, and because the omega's bone structure is not built to shield the womb in the way a woman's is. An omega pregnancy is rarely longer than six and a half or seven months, because the male body does not have the superstructure for supporting the fetus, and because the normal sized human baby is just too large for the omega to safely, and naturally expel. Ergo, omega-bourn babies are almost always a bit on the preemie side, and infant mortality is as high as childbirth mortality – better than 35%. This is another reason why omegas tend to attract packs – because they are fragile in their pregnancies, and they require more support than a woman does doing the same job.
They are able to do less, risk less, eat fewer things, and they feel more pain from it. They literally NEED the protection and support of a pack around them if they're to have a chance of surviving to bear more than just the one child.
So that explains omegas. What about the alphas? What's this rut thing you kept talking about?
Rut is the alpha answer to the hormonal dependency the omegas go through.
Given that omegas needed alpha hormones to conceive, and the human race was fighting extinction at that point, the species fine-tuned alphas to be particularly receptive to, and even dependent on omega hormones as well. Alphas can be fertile with women, though it's not constant enough to bet on, but they are far more fertile with omegas, due to the hormonal sympathy going on between those two statuses.
The omega sexual hormones act as antidepressants and mood stabilizers to alphas. Regular sexual contact with an omega is a way to get the strength and vigor of an alpha without the asshole factor always getting into the way. It also means that alphas imprint on a particular omega quite readily when they're given the chance, and tend to become protective, loyal, and devoted over time. (More on that later.) Unmated alphas tend to become very depressed and self-destructive over long periods of time. (And by unmated, I actually mean celibate, not unbonded. Bonding is a whole other thing.)
One way that many cultures have dealt with this, is through creating omega enclaves, where strangers can meet for safe, anonymous relief. Alphas are admitted as a kind of supplicant to these enclaves – only ever alone, never allowed to bring possessions, or even his own clothes in, never allowed to encounter other alphas in the enclave, and never allowed to stay once they have helped one omega through his heat. (Afterward, it is not uncommon for that omega to sort of spread that alpha's seed around to other omegas who need at least some temporary relief from their own heats.) This arrangement puts the omegas in control of the arrangement, which is held up socially as only being fair, considering how vulnerable they are during their heats.
Alphas who spend too much time with or near omegas who are in heat, but to whom they can't get access can go into rut, which is a state of sexual obsession that overshadows basic social functions to ridiculous levels. It can occasionally be violent, but most omegas can tell when an alpha is getting ruttish and will avoid him, and alphas can usually tell when another is getting ruttish, and will not actually let him near an omega he might hurt. Some alphas do not get violent when ruttish though; they will stop eating and sleeping, stop physically caring for themselves, stop caring about social conventions. They will masturbate when they feel they must, which will be frequently, and they will display territory marking behavior. Some will go non-verbal, and seemingly regress into a childhood state.
If a sympathetic omega is not willing to help the poor guy out, sometimes the rut can be broken by an omega child spending time with the alpha until he balances out. The child is not in danger, as he will not be putting out attraction hormones that would bring the alpha to perceive him as sexually available, but his skin and saliva will still contain trace amounts of the omega hormones the alpha is craving. Barring that, ruttish alphas have been known to be calmed by being given the stained bedlinens from an omega's heat, though that solution rarely works for long. If a ruttish alpha shows up to an omega enclave he might be admitted if there is an omega inside who chooses it, but if he is, he will almost certainly be restrained in some way for the encounter, just to ensure the safety of the omega he will be mounting.
And Betas? Where do they come in?
Betas are what's left of humanity's basic male variety. They are most fertile with women, they react to omega hormones with interest, but not with the kind of compulsion that alphas do, and while they experience something similar to heat, it's acutally a sympathetic hormone cycle in aid of nothing in particular. Betas are a little more fertile than otherwise when they're heated up, but they cannot conceive, only sire, and usually only with a woman. (When one stripe of humanity develops such a strong sexual expression, it's not a stretch to say that others would evolve a mimic to it, as I've got betas and women doing in this culture.)
In pack structures, they tend to be the questioners, the rule-testers, the ones who shove at the box to make sure it's sound – but they also tend to have a strong provider streak, especially when one of their alpha/omega pairs is in seclusion. They are inclined to challenge, but they are still very loyal, especially to those they feel need them – pack children have, in their betas, the most indulgent and protective of godparents. Betas are also frequent adopters of abandoned and orphaned children – something that happens often, given the perils of omega pregnancy, and the frequency with which humans kill each other in general.
Betas are fully capable of leadership positions (all statuses are, really,) but they tend to be exhaustive planners, obsessive of detail, and always very conservative in their decisions. They are used to challenging the rules, not setting them, and so they tend to almost overthink it when they have to be the ones imposing the structure. The general social understanding of things is that an alpha's too reckless to lead by himself, an omega too nice, and a beta too cautious; the only way a pack gets anywhere is if you've got all three cooperating. As with all generalities, it's flawed, but at a high pass, not untrue.
Howard Stark was a beta, and a very atypically reckless one in his early years. Later though, he began to exhibit some of the control-demon behavior that was more typical of a beta without an alpha to push against.
Obie was an alpha, but Howard took care to make sure he never got enough power in the company to depose him. And we all know how well that worked out...
Okay, so in a world where there are breeding males and very few women left in the world, where to women fit into this matrix?
Well first and foremost, even with the human mutation that allowed for omega males to exist, human women STILL are better at conceiving, carrying, and giving birth to healthy babies. Their pain thresholds are higher than males, they have better endurance for the process than males, and they are biologically and structurally better suited to the task. This means that, especially in early human history, women were incredibly prized, and in most cases treated very well. (Yes, there will always be abuse, rape, and atrocity, because we ARE talking about humans here, but with women being that rare, there are plenty of alternatives a woman can have if she is not satisfied with her treatment. Abusers learned this pretty quickly.)
Human women in this world were more empowered purely by being so rare – and also by being thickly interspersed (at first) with Jotun warriors who, though presuming themselves women, still knew themselves for warriors and the equals of their peers, no matter the sexual equipment in question. A woman who was not happy with her treatment could very easily find someone to offer her a better situation, and while some cultures made an effort to imprison the women as property, the presence of the Jotun warriors in their midsts made this just not work as effectively as in our own history it has done. Feminism got an early start on the heels of the invasion, with women working out how to use their own value as a bargaining chip, and as power in their own hands. The struggle wasn't seamless, and there were many backslides, but despite being a much more diminished minority in this world, women have managed the same accomplishments as they have in our own world – and a few more.
One of the biggest differences for women in this world is that their connection with education, medicine, and sciences was much more open, and happened much earlier in most cultures. Since risking injury to a daughter was a foolish thing to do, girl children were typically kept from raucous play, dangerous work, and risk of kidnapping by schooling them. This lead to a far greater presence of women in academia as far back as the Greek and Roman times, and carrying straight on through to the modern West. The shape of Women's Lib in the a/b/o world had more to do with them fighting to be allowed free passage and the right to risk themselves physically, than having to fight for equal rights to education and job resources.
Peggy Carter's presence as an officer in the military is just as much (if not more of) a shocking thing for this world as it was in our own. By the beginning of WWI, the population of women had recovered to nearly 25%, and that percentage didn't noticeably shift during the influenza pandemic that followed there. Between the male casualties of the war, and the girl-boom that followed, the human female population is now approaching %35, and women are much less sheltered/protected than they had been before those two wars.
But how do women fit into the whole breeding cycle thing you've described?
Here's where that wacky adaptive human biology comes into play. When omega males, with their strongly hormone driven, pheromone-advertised estrus cycles, emerged in the human genome, human females adapted a competitive response to it. (No, this was not a conscious choice they made, this was a species making every attempt to assimilate the new genetic data in its pool, and to keep itself from extinction.)
As a result, women began to experience their fertile periods with the increased pheromonal output, and a much stronger estrus-response that would match in symptom the omega heat. However unlike omegas, females are more or less fertile anywhere in their cycle – pretty much as they are today. And given the biological superiority of their skeletal structure for the purpose, they tend to give birth more safely, and to carry their babies longer than omegas do. And to be able to do it more often over the course of their lifetimes, as well. They hold a solid position in society, but they definitely adapted to the stronger hormonal presentation with a ramping-up of their own scent-markers.
In general, women are pretty much as they ever were, with the exception of being more sensitive and reactive to the hormonal breeding cycles of their male counterparts, however the social habit of ranking women according to their apparent behavior is long-standing. Women who are sensitive, shy, or deferential in manner are considered omega, women who have a strong tendency toward caretaking, management, or organization are considered beta, and women who are dominant and/or combative in personality (or known openly as lesbian) are considered alpha, despite their biological similarity. These rankings have nothing whatsoever to do with their biology or their sexuality, it's just what their male counterparts reflect upon them, because that's kind of what humans DO.
A twist upon this is that Erskine's serum actually did bring about true hermaphroditism in both of its successful tests. Both Steve and Peggy express as both carriers and quickeners. And since Zola's attempts to replicate Erskine's formula were based on stolen, early notes, there have been increased numbers of actual, real female alphas in the girl-boom that followed the end of World War II, and the liberation of the breeding camps. These new, actual female alphas do have a penis that works much as the female spotted hyena's does, and while they can conceive and bear children, the childbirthing process is necessarily caesarian and early term, like an omega's get.
Peggy Carter was never pregnant herself, but she wound up marrying an omega, and her descendents were all carried by him.
One of the major social changes that came about due to the shift in gender demographics and powers, is that mi midwifery science and early natal care are FAR superior in this world. More women in official medical studies, more focus on making childbearers live long enough to do it again, and more focus on preserving quality of life overall were inevitable to the new arrangement, and the rarity of children for awhile.
Cesaerian birth is quite safe by comparison to our world, and medical science focused pretty quickly on the problem of keeping those tiny, early babies alive and healthy so they could grow up. Parenting via pack quickly became a thing however, given that Omegas just have a harder time giving birth than women do, and so even with the improvements in medicine, the childbirth mortality rate is still fairly high, and it was even higher in the middle ages, when sanitation was less well understood. Ergo the cultural slant turned toward cooperative packs who served as the co-parents of any child that entered their orbit.
Great, so how the hell do all these packs and imprints work?
Due to the strong influences of pheromonal communication, most of these packs identify, and rank each other by swapping fluids -- sweat in a protracted nuzzling session, or by stealing an alpha's clothes between washing sessions; saliva by way of kissing or licking subcutaneous glands; semen and seminal fluid through sexual transfer, or by access to the omega's sheets and clothes after a heat; blood in certain situations involving deeper pack bonding and dominance rituals. Humans being evolved to sapience before this mutation occured, it is an extremely weird thing for urine to factor into these bonding rituals, but yes, the kink is there for some. When, after all, have humans not been kinky fuckers?
So the primary difference between an imprint and a bond lies in intent. Imprints happen through prolonged, repeated normal contact, and they're just a chemical stabilization to the kinds of emotional connections that all humans make anyhow. Several kinds of imprint also dovetail into commonly recognized packbonds, but the significant difference between the two remains that you have to DO something to create a bond, whereas an imprint just happens.
Imprint type A) bloodline passive, as expressed from the sire/dam to their child until the child develops secondary sexual characteristics and begins to put out its own identity scent. At this point, the child, through skin contact with its parents, will absorb the scent markers and hormone output of its parents, and will imprint to them, incurring powerful protective bonds between them, which will survive the child's own sexual maturity more or less undamaged. This is not unlike the oxytocsin release that informs our parent/child bonds in the world we know, however it is stronger, due to the very strong extinction threat, and the extreme vulnerability of the infants born to omegas. Parental imprint is one of the strongest bonds in the a/b/o universe, and because of it, bad parenting is a rare thing indeed.
(Howard is a very abnormal instance, and most likely actively refused to have much contact with his infant son, in order to be as indifferent/neglectful as he was. Edwin Jarvis, apparently, assumed the parent imprint for Tony somewhat, but not until he was older than he should have been for it. And Bruce's father was an even more abnormal instance. Adults who beat their mates and children rarely keep them – other adults almost always intervene and remove/adopt the threatened ones.)
Imprint type B) denning / sibling imprint; Living for a long time with someone else's scent, no matter their status or yours, will create an imprint of social acceptance between the individuals, like having a brother or sister. They might very well dislike each other deeply, but their hormonal output will drive them to look out for each other to at least some degree, and to find some kind of balance between them. This is the imprint that Steve and Bucky shared from childhood – it required no activity of their own to enforce or create, it just happened because they lived for so long in each other's pockets while they were both coming into their sexual maturity. The fact that they loved each other was not dependent on that bond, but the imprint didn't hurt things at all. Similarly, Pepper and Tony developed this kind of passive sibling bond (though over a longer time, due to less constant contact, and it coming at an older age) between them.
Imprint type C) social / shared territory imprint; This is an adaptation that arose in response to the establishment of cities and towns over nomadic style packs. In this structure, any individual whom you cross paths with regularly without conflict – as in, shake hands with or even hug in passing, -- will establish a non-threat imprint on a subconscious level that, while not as strong as a pack bond, will still assist in neighbors keeping their peace, and rallying together to support each other at need. The bond medium here is skin secretions, either transferred via contact, or through scent exposure, though that requires more time to settle in.
Imprint type D) Courting / sexual priming imprint; An Omega can pick up a passive, social preference for one particular alpha if he spends a great deal of one-on-one time with him in the days coming into his heat cycle. This is generally achieved through scent-influence, and it's easily shaken off if the omega feels threatened or disrespected. This is one of the reasons why omega enclaves came into being in the modern era, so that omegas who were coming into their impressionable period could remove themselves from unwanted scent influence until they were ready to get the heat over with. Like most passive imprints, this medium is entirely scent-based, with some reinforcement from skin contact or saliva (kissing.) It is not absolute, nor does it cloud the judgment, but it tends to smooth the complications of heat cycle somewhat.
Imprint E) Courting active / mate imprint; An omega goes through several low heats per year, but only one or two heats will be 'breeding' heats -- that is, a heat process that lasts for more than a couple of days, and strongly impairs the omega's normal function unless he is exposed to alpha chemistry. Of those breeding heats, in order for an actual pregnancy to result, the omega needs to have had repeated sexual contact with a particular, suitable alpha for at least two or three consecutive heats -- as in, the same alpha. That alpha's seminal release triggers long-term, slow changes in the omega's body which allow the internal organ structure to adapt for the potential of carrying a child. If the environment is too stressful, (emotional duress/distress, lack of resources, or unstable living situation) or if the contact with the alpha is not stable enough, or does not happen with enough consistency, then the Omega's physiognomy will not respond, however the mating imprint will take, and the pair will begin to respond to each other as if they are a bonded pair until a pregnancy results.
Bond type A) hunting / warband bond. (This bond blurs the lines a little, as it's partly incidental, but not entirely.) When individuals set out to hunt, or to fight together, there will almost always be a strong hormone release from whichever alpha they have assembled to follow. The band will tend to push against him, and each other, in a jostling, ramping up kind of behavior, inducing them all to sweat a little, and to share the scents of each other uniformly through the band. Biologically, this increases pack recognition, cuts down on 'friendly fire' instances, and helps to keep an alpha from killing his own if he falls into the red during the fight or the hunt. Packs who fight or hunt together always eat together afterward, and often sleep (as in sleep, not sex,) together as well, until the adrenaline-high scent fades away.
Warband Packs like the Commandos, who were frequently in the field together, bear a bond that's almost as solid as a bloodline bond, due to being constantly reinforced, and those packs will take on familial structure roles, with the betas being the caretakers, the omegas being the peacemakers, and the alphas being the providers, at least symbolically. Warbands frequently taste each other's blood when there are wounds, and this is often done without thought, but it is one of the ways that the warband bond establishes and maintains its structure against the stress of frequent combat, and occasional loss. Of course the bonding hormones are expressed in the blood as in other fluids, but the blood bond is actually the weakest type. The mutation being sexual in nature rather than combative, blood is not the ideal bonding medium, and tends not to really last too long comparitively.
Bond type B) denning / adoption bond; Due to the high mortality rate of omegas in childbirth, the extreme value of children after the near-extinction event, and the vulnerability of infants born to omegas (and therefore gestated for a shorter time than those born to women,) packs needed a way to insure that orphaned children would not be lost, either to harm, or to other packs, even if the children in question were independently active, or even undergoing puberty, and to overcome any adult tendency to abuse or neglect the get of another in favor of one's own. As the population numbers stabilized and the stronger packs showed their evolutionary advantage, this adoption technique extended to lone adults seeking to join an established pack's social protections.
There is an element of ritual to this, hence, 'active', involving the pack's alpha and omega both offering food and drink to the newcomer, who eats and drinks, then submits to his skin being licked by them, and by other members of the pack, who scent-mark him thusly as their own. This licking behavior can repeat over a pattern of several days, with pack members licking wrist or throat as a kind of greeting until the newcomer's place within the pack structure is understood. While this ritual is intimate, it is definitively NOT sexual in nature, or in expression. There is nothing in this ritual that triggers a sexual response under normal circumstances.
Bond type C) Clan building bond. A more intimate, less neutral bonding imprint that can be established in instances where several strangers are put into prolonged contact, or forced to cooperation – such as prisoners or refugees, or survivors of tragedy. It involves a core omega and his chosen alpha sharing a kind of sexual contact with the rest of the pack during the omega's fertile heat cycle. When the omega is knotted at that time, he secretes a strong oxytocsin-based fluid, similar to precome, from his penis. Others of the band, regardless of status, will either taste of this, or will rub it on themselves to create an instant familial bond between them all. In a way, this is a mutual adoption of all the pack members into family status, and it is both intimate, and sexual, though it carries no implication or drive to repeat the sexual aspects once the event is over. Packs with several omegas sharing territory might very well repeat this ritual when each of them, to assure equality. Generally, a pack choosing to do this will do it several times, in order to reestablish and reinforce the chosen bonds. They will also do it again when they lose, or add a new member to the matrix. The immediate effect of this bond is a chemically induced empathy between the members that fades in intensity over the course of a few hours or days, to become essentially identical to the sibling/parent/birth-pack form of bond. Obviously, this is the pack bonding that I've illustrated in Changeling for the Avengers.
Bond type D) social dominance bond: This is another ritual style of imprint establishment, one developed to keep wandering loners from getting killed as they'd pass through pack territories. It further adapted when employment outside of one's pack became a normal thing. It involves the show-of-dominance of a bite marking, as well as the temporary scent-marking of the dominant individual's saliva on the recipient, both of which he will carry on him while he is in the pack's territory as a kind of 'pass key'. In modern times, this ritual has faded significantly down, where now a new hire will generally only be given a token item from their boss – a handkerchief or wrist band, for instance, -- and will only wear it/carry it for a day or so. Many dominant individuals, like landlords, superintendents, hosteliers, priests, teachers, and suchlike, no longer extend, or expect this kind of acknowledgement, and other authority figures like politicians and law enforcement would never be extended such a hold in modern times
Bond type E) An adjunct type of imprint that arose in the medieval time, and has been taken up occasionally by various cultures in the modern time, is that of the proxy imprint, where an alpha will, through the mark of his bite in an obvious place, turn over temporary leadership of his troop to another individual for the duration of the mark's visibility. This is an antiquated practice though, harkening back to the middle ages and colonial times, when packs could be isolated and very dependent on each other for survival. It has little place in modern times, though it is still sometimes practiced by extremists and kinksters.
Bond type F) Courting / pair bond; When an alpha/omega pair have established, repeated communion, compatibility, and stability, they can establish a deeper level of connection and relationship permanence by exchanged biting over a particular scent gland during the altered chemical state of being tied. Essentially, during the shared orgasm, certain glands become responsive to direct stimulation, and doing so on a mutual basis will alter the scent mark of both individuals. If repeated in successive heats for a period of time, this scent alteration becomes a permanent thing, reducing the availability/attraction factor for the omega and alpha both where strangers are concerned. In a way, this creates something like an addictive dependency on a particular person, the withdrawal from which is really a difficult thing – hence the social assumption that bond survivorship is hell, and survivors frequently suicide rather than endure it.
Okay, so that seems pretty clear. Why the hell was Steve freaking out about it?
In Steve's time, sexual education was a thing handled exclusively by parents and church elders. It was not until the sexual revolution of the late 50's and early 60's that sex education became commonly addressed in schools. So as a result, Steve was never actually told much accurate information about any of the other rankings, or about girls either. Most of what he came to adulthood 'knowing' was filtered through the behavioral control training of the orphanage nuns, or whispered from other kids trying to impress each other with bullshit. So he has a stilted understanding of his birth-status, what would be expected of him, and what role he would play in any cultural situation. Then when his status is changed to include all possibilities, the only people who expected the meta-alpha result, and could have sat him down to explain what he could expect were Doctor Erskine, who was killed, and Peggy Carter, who was sent to London immediately. When she caught back up with him again, Steve had learned and worked out some things, but a lot of the subtle social bonding information he would have been taught if he'd grown up an alpha, he never encountered at all.
Likewise, Bucky's understanding of being an omega was entirely informed by his orphanage upbringing, and the pornography of his time, and as such was wildly distorted. A large part of the dysfunction I have portrayed in that pairing arises from this sense of status-dimorphism going on with each of them, and the struggles they're going through to adjust to the changes, and to work out what's expected of, and allowed to them.
The tragedy there is that if both of them had had just a little more time without the war in the way, they'd have figured everything out, and come together just fine. On some level, Steve realizes this.
Also, for the purposes of this story, Natasha is Bucky's child by Steve. I vaguely hinted at that, but I want to say it outright here. She was the child Steve thought he might have lost, but never really knew. She would have been a natural alpha, but the Red Room neutered all of their young operatives before they could express their sexuality as a matter of course, preferring the adaptability of an operative who could mimic any status with the use of perfumes and prosthetics over one who might be compromised by internal, biological chemistry.
The sexual nature of her contact with Steve being limited to the pack bonding process, it's unlikely either of them would be specifically horrified by that exact detail of it if the relationship were verified -- they'd be far more concerned by other things instead. However, as not even Bucky is aware of the relationship, even when he was training her for the Red Room, it is unlikely that any of them will ever put the details together. The only people who were in a position to know for sure are dead, and barring anybody putting a genetic scan of all three together to compare details, there's no way they'll find out. The pack bond will be particularly sticky between Steve and Natasha though, given the biological predisposition to it that's already in place.
Okay, so what's the deal with the poly-bond thing Tony was teasing Coulson about?
Another thing that arose from the sexual revolution aside from birth control, and better rights of choice for omegas and women, was acceptance of beta/male pairings -- essentially, homosexual-by-preference relationships.
In Steve's time, betas went with women, and only concerned themselves with omegas if there was no alpha around to do the job. Betas who preferred the company of either alphas or omegas were considered bent, broken, deviant, and all the other things that translate to homophobia in our world. The sexual revolution began to change that, but it's only been in the last decade or so that legal protections for beta/male and female/female relationships have begun to be set down. Pair bonding laws are on the books in several states, and the only reason Phil and Clint are not currently married is that they can't legally do so with Natasha too, and they don't want to leave her legally out of the mate-bond they already share between the three of them.
She would actually agree, if it were legal for the three of them to be married, and learning that would surprise them all more than just a little bit.
They still swear by Christ, I notice; how does that work within the a/b/o world?
Christ was an omega, and clearly recognized as one in scriptures. He was the pack core of a gang of betas, alphas, and women, but scripture has been stripped of any reference to him quickening, mating, or even experiencing a heat. So it is from the traditions of Abrahamaic Religions that heat-enclaves, and omega isolation arose. It bears some similarity in our world, to how women are essentially expected to quarantine themselves during their periods, only without the implication of uncleanliness. The implication is that to remain safe, and pure for the alpha to whom they will later bond, they must retreat from society and from the company of those who might react to their scent with impure action and thought. The 'beloved deciple' is understood to have been a beta, and therefore unworthy to bond with any omega, let alone the Son of God, which means that the Church is still a driving force behind the anti-gay culture in the world.
Christian canon is full of saints who were martyred on the basis of their heat/rut cycle, and I'm sorry to say it, Catholicism is just as fucked up about sex and sexuality as it ever was. One interesting change though, is in the sacrament offered at mass. Now, instead of eating the host and drinking the wine, the sacrament is offered in a dish of oil, where a dot is painted over each eyelid, and a dot placed on the tongue, mirroring the pack-bond ritual presumed to have taken place between Christ and the Disciples. However it is never addressed how Christ might have possibly released the bonding-milt if he'd never been knotted. Just one of those 'where did Cain's wife come from' problems, ultimately -- good believers just don't ask about it. Another tradition that's arisen in the church relative to this, is that the priesthood is seriously FULL of omegas. In the history of Rome, there have been perhaps two or three Popes who have been of any other status, and one of those was murdered by his guards, while another was most likely assassinated.
The symbolic power of omegas has been pretty high for most of history, but the actual authority and power of most of the status has not been very stable or strong. Women, being exceedingly rare, were likewise very highly commoditized, but also because of their rarity, had much of their independence removed by most societies. Women have very much been property in this world, chiefly on account of their rarity, and their superior ability to not only conceive, but to survive repeated childbirths.
Also due to the rarity of women in early human culture, the title of Queen does not refer to a woman exclusively, but rather to the person who will give birth to the heir. Ergo, Elizabeth the first of England, and every unmarried female monarch that followed her, have been known as KING unless and until they married. The title of Queen was something a person earned by becoming pregnant, and in fact it was something of a tradition in the West to leave the Queen's coronation until quite late in the pregnancy, so that he or she would be very obviously gravid at the ceremony. The objectification of pregnancy was, and still is, a big Thing in this culture, and as such many uniquely feminine health concerns were studied much more carefully in that world.
With so few women in the world, losing them to preventable medical conditions was unacceptable. Also, midwives weren't ever persecuted, but were rolled in officially to most cultures' medical practitioners and studies, so female doctors are, and were, a rather common thing. Sarah Rogers was, in fact, a doctor rather than a nurse, and her decision to work with tuberculosis patients was allowed because she'd caught a near-fatal dose of influenza just after Steve was born, and the high fevers had rendered her sterile. So since she could no longer conceive, the hospital officials allowed her to work in the TB ward. The pay was higher because of the risk of infection, and she needed the money because of Steve's sicknesses.
The girl-boom following the war was what gave real strength to women's fight for cultural power. There'd been some strides in America before, at the point where historically you'd expect them -- women's suffrage, and suchlike -- but the sudden appearance of so many more females in the world gave lawmakers enough pause to consider their needs beyond their capacity to procreate.
So there. There's a few of the worldbuilding notes I had in mind while creating this ... um... it's a novel, really, isn't it? I guess I have to admit that it is. Anyhow, I hope this has answered some of the questions you'd had. I'm not into hardcore graphs and charts kind of biology, so I'll leave the chromosome mapping to those who will do it better and more accurately. You'll have to be satisfied with soft-sciences of anthropology, behavioral studies, psychology, and forensic history here. (Yes, I kinda made that last one up, but it's totally legit when one is playing the 'what if this one thing changed' game, and so say I.)
If there's anything else you want to better understand, or contribute to this meta, by all means say so in the comments, and let's chew it to pieces between us. I love that kind of idea interchange, so long as it's respectful and enthusiastic.