So we've gone from my hand-wavey definition of 'innate' talent to your hand-wavey definition of 'emergent' talent.
I didn't mean to imply you were wrong, just that I disagreed with the view of inherent talent on a personal philosophical glass half-full/empty level. I see everyone as being limited, and people with "natural talent" are just less limited in some way.
Human potential is so unimaginably high, that I don't think anyone ever reaches their potential. Take a child from 3000BC and raise them in a (rich) modern environment, and they'll be able to achieve a level of knowledge that's beyond comprehension of their siblings that weren't lucky enough to get into the time machine. In the same way, it's imaginable that there exist conditions in the aar future that make our modern upbringings look extremely primitive and undernourishing.
Innate talents are something we can talk about; they exist at that level... but they're not real... in the same way that a physicist isn't satisfied with atoms, and instead wants to look for quarks. There's an underlying cause and effect, and those effects can be harnessed.
Some people are bad at a skill, even when performing extreme amounts of practice, simply because they're thinking about it wrong - they're using the wrong bit of mental hardware to perform the task. They can sometimes be taught to think about the problem differently, but not easily, depending on their mental flexibility. Once you start practicing a skill, you reinforce it and if you practice too much in the wrong mode of thought, you might just be concreting your inefficient mode of thought and limiting your potential.
Some people are bad at a skill because their mental organs simply aren't as strong as other people. Like a muscle, you can train them to be better bits of computing hardware. Often, training in the task you want to be better at isn't always the best way. It can be useful to train in many different tasks that all use that area of the brain in order to strengthen it.
The article you linked to is basically talking about genetic predispositions. These are very different things than actually "being genetic", and are the grey-area truth between the stupid nature-vs-nurture argument. Having or not having a predisposition doesn't mean that you will be good or bad at something though, it's just an indicator that the best method for teaching you that thing will be different to others. The "best" environment for a person depends on their predispositions.
Take someone who's predisposed to having great pitch, and raise them in a community of silent monks in a silent valley, and their predisposition probably won't come into play. Take someone who doesn't have that genetic marker, and by chance, have their tone differentiation lobe receive an above average amount of stimulation in early development, and they might end up a maestro... or, have them practice read a lot in early childhood and develop a large vocabulary, and they'll be exercising the same organ!
For example, a genetic marker for a predisposition to drug addiction was found by analyzing a large number of drug addicts. In a second (wider) trial, the marker was also found in larger numbers in the general population of non drug addicts. On further analysis of all these subjects, a significant correlation was found where people with this "predisposition gene", who suffered violent abuse at around age 5, were very likely to go on to become drug addicts, whereas those who grew up without violence were unlikely. So, what seemed to be a straightforward genetic link, is actually intertwined with environmental factors.
There's many genes like this, which are present but not expressed (not "turned on"). When some particular event occurs in the mind, then that switch is flipped... which means that our very thoughts can interact with our genetics. The truth is very grey.
Identical twins also do not have the same fingerprints. That’s not magic—just genetics.
Fingerprints are the perfect analogy; they're not genetics at all. Fingerprints form their unique patterns depending on how you bump around with your foetal environment. Your mind is formed in exactly the same way - the chaotic bumping into your environment.
When does “innate” talent become present in a person? As far as I know it is as soon as they are born. I honestly can’t remember a single day in my life when I was not able to draw realistically.
No, you weren't born with the talent of realistic drawing. You could hardly even see properly when you were born, let alone have the dexterity to hold a pencil. No, you learnt to draw in childhood like everyone else (or, not quite like everyone else).
The difference between someone who draws realistically and someone who draws crude outlines is the part of their brain that they use to perform the activity. We don't all see the world the same way. The same light goes in our eyes, and mostly the same signals get sent to the brain, but there's many different ways in which those signals can then be processed and "seen" consciously. People raised in different cultures will literally see the world differently -- scan their brains to see how they're processing the visual information, and there's major differences.
The "artist's mode of vision" occurs typically in the right hemisphere, and extracts detailed information about composition, curvature, lighting/shading, colour, etc... On the other hand, the typical non-artist mode of vision occurs in the left hemisphere and extracts information more useful in our day-to-day lives, such as large-scale form, object classification, etc... Most people use the 'left mode' so much that the 'right mode' becomes so atrophied that it's almost impossible to use. Through mental training (not necessarily artistic training), you can teach someone to use this mode of thought, and to 'see' the way you do naturally.
In your case, you bumped around in just the right way that both these modes of vision were well exercised, and thus found it natural to slip into this mode of thought when drawing, leading you to early talent. It's impossible to say when this happened, but it's the accumulation of every event in your life from conception up to that point. Your mind develops at an inversely exponential rate, and the amount of development in your first 9 months is phenomenal You could well have had above-average visual/spatial processing abilities at birth, but could have also developed them later.
It could have been the above-average development of a particular brain lobe, or the below-average development of another (which caused you to compensate by using other parts more, strengthening them), or both, or neither.
I remember when I had just turned 4 and was in pre-school when I saw a girl in my class drawing her grass like huge sawblades and I tried to show her the correct way to draw grass as little strands, and some asshole bully told me to pick on someone my own size (huh??).
If you see a child expressing themselves artistically, and you go and tell them that they're doing it wrong, they'll very likely become upset, confused and offended. A child overhearing your remarks will react the same way empathically. This is off topic, but it's a good opportunity to point out that many of the down-votes that you get on this site to this day are because of the same kind of miscommunication, where your good intentions are betrayed by a lack of tact.
I have hated every moment that I have spent drawing except for a few very rare gems, and yet some of you people have the gall to say that my level of art could only come from hard work and motivation?
I didn't say that at all.
Someone to whom drawing doesn't come naturally could improve their possibility of producing similar results, given enough hard work and motivation, and the right circumstances. Not necessarily hard work at drawing, either. The brain regions used for drawing are also used for so many other skills -- it's a shared bit of hardware, so hard work to exercise and strengthen that hardware will benefit all of those skills.