A Theory on Nobodies and Birth is a research paper composed by Jazz out of character, and by Jinx in the OE universe. It is currently in the possession of Professor Xelgaeb, who is testing and improving it.
A Theory on Nobodies and Birth Edit
The first thing you must take into account before reading this theory is my take on the Nobody race. There are, after all, several schools of thought on how they work in a physical sense. In the official cannon of the KH series, nobodies as made of "nothing" and are little more than hollow shells taking the form of the person they represent. These nobodies are thought to lack blood and therefore logically lack any form of internal organs.
One of the other views on the nobodies, the view embraced by not only I but the entirety of Organization Eternal and likely many others, is that the nobodies, specifically human form, are essentially human. To lose a Heart is to lose an intangible, spiritual part of themselves and thus for the most part minimally affect the body. And since nobodies are essentially human, they can indeed reproduce the way any human would, unless there is something else preventing them for example, they have been "fixed" or were not originally human and thus are incompatible with "true" human forms. This would be someone who was originally an animal, such as Xirak from Organization Eternal who was once a lioness of the pride land. On that note, why all nobodies take on a humanoid form is for the moment unknown.
When a nobody conceives a child, there are generally to possible outcomes, both of which I will attempt to explain as well as for the most part prove as pertaining to the view of nobodies that I personally accept. Firstly, the child can be born as a whole. When this happens, then possess no power, no special abilities, no heightened senses or resistance to darkness. They are simply whole beings. I don't say 'human' as Nobodies are not always completely human. For example, Annex, son of Moxstr, had a father who though also a Nobody was a demon. As such, the demon blood carried over into him and manifested most noticeably in his scales, horns and tail. Annex himself however does not fall under the category of "nobody born wholes". This wholeness comes naturally as the baby will naturally develop its own Heart. The Heart is as much a part of genetic coding as say the liver or they eyes. Though (likely) both parents lack their own, the base code to a Heart is mingled in with whatever code that writes the soul in new life. Though possessing no special powers, whole children born of nobodies will naturally have stronger Hearts then other wholes, simply because of what they were exposed to during growth. They can also have a stronger resistance to darkness, depending on how much of it they were exposed to during growth. The Heart doesn't begin to develop though until nearly three months into growth.
The other possibility, and from what I have seen the more popular course of action, is for the baby to be born a Nobody. This can happen in several ways. First, and more often than not and accidental method, the child is robbed of the 3 months it needs to develop its Heart. A prime example of this is Jinx's first known child born in her first year of Eternal with the now deceased Xeran. Not wanting to wait a full nine months, Jinx asked Xeros to alter reality as her power allowed and skip the pregnancy along to the very end. This sudden skipped stole the 3 crucial months needed from proper Heart development, resulting in Leon to be born not only without a Heart within him, but with no Heart at all as one was never even developed for him. The second scenario that could end in a child losing its Heart can be heave exposure to darkness while still within the womb. This can happen through excessive portal travel, direct exposure to Heartless through battle or infection from the more powerful breeds, or possibly even the mothers own thoughtless over use of her powers, even though many power have little to no tie with darkness. The over taxing of the mothers body can, in turn, put immense strain on the child ending in not only adverse effects on the Heart, but it may also hurt the child physically.
Even if it's never exactly a good thing to lose a Heart (and even that depends on personal opinion), there is an advantage to the child developing and then losing their Heart, opposed to not even having the chance to grow one. As long as the strain is not so great that it causes the young Heart to break down and essentially die it will, like all other Hearts, find its way to Kingdom Hearts, thus giving the child a chance to one day regain its Heart alongside it's parents.
Though the phenomenon is yet to be explained, children born as nobodies have a tendency to grow at a drastically accelerated rate, even before birth. An unborn baby that has lost its Heart can develop in as little as 2 to 3 months. Once born, the ageing process varies from child to child. Some have been known to age as quickly as roughly a year per month to something closer to cat or dog years. Eventually, the ageing tends to plateau in an age range between the late teens and early twenties where the Nobody will stop aging and physically growing for the most part. Again this is a yet to be explained phenomenon. Children born as nobodies will have a select power and weapon, just like all others of its race, though these they will have to discover on their own in the later years of life. Generally, their powers will stem in some way from one or even both of their parents, though this is not always the case. The weapon itself will only develop once they reach their maturity (when their growth plateaus).
Another possibility, though by far one of the most unpleasant, is the mother dying during her pregnancy. Under a normal circumstance and with nobodies as well, it is extremely rare that a baby would survive the death of its mother while still in the womb. It would have to be within weeks of the due date and there would need to be immediate medical attention. For a child whose mother is a Nobody, this already slim chance at survive is even less likely as they are tied to their mother in both a physical and spiritual sense still. As the mother fades the child, whether they be whole or Nobody, will begin to fade along with them. It requires a conscious effort on the mothers' part to rip herself free from her baby and hopefully spare their life from her own. Again, even if she manages this, it's extremely rare that child will survive but it is possible. The second possibility if the mother finds herself dying is painful to say the least. In nobody woman who don't have nearly as strong a mothering instinct, or possibly none at all, it is possibly for her to save herself by essentially cannibalizing her own babies Heart. She will only be able to pull the part of the Heart that comes from her side of the DNA, leaving the childes Heart in shredded remains and undoubtedly killing it. Though this may result in saving the mother from fading, she will be left in a state of "half existence" and very likely a guilt that will follow her to the day she dose die. On this topic, if for some reason the child dies before birth, their Heart and soul will behave as any would in a natural death.
It is NOT possible to be born "A Nobody with a Heart". This is a direct contradiction as to what a Nobody is. They are either born with or without a Heart.