There is constant argument between those who think that human beings are largely the product of nature (their genetic inheritance) and those who see nurture (their upbringing and formation) as more important with sometimes the balance falling on one side and sometimes the other. It's a strange debate. Both elements are a factor in what a person is with the deciding element practically always being nature. I would say that's fairly obvious.
However I would like to introduce a third factor into the mix. There is our genetic inheritance, of course, and there is our cultural formation, also of course, but there is something else too which is rarely considered. That is the soul.
I believe in reincarnation and I think that a soul evolves spiritually (and in other ways but spiritually is the most important) through a series of lifetimes in this world. Now, I don't know whether all human beings go through this process or only some but even those that might not do so have a pre-existence in the spiritual world. They are not newly created at conception or whenever it might be. Their spiritual creation precedes their material one.
But let me take the reincarnation scenario first. In this scenario, God creates individual souls on a spiritual level whose consciousness when created will perhaps be similar to that of a new born baby. No real sense of self, no capacity yet for thought. They are enveloped in a kind of passive blissful oneness. They come to this world to develop, first in ways with which we are familiar, bodily, emotionally, mentally and so on, and then in a spiritual sense as they grow out of their ego into a wider sense of union with life but this time experienced consciously. They start off ignorant children and end up saints. That is the aim anyway, with this world, essentially a world of duality with the awareness of God removed so that the soul may grow as an individual, the theatre of operations for their education.
This means that each human being has a spiritual past. We are not just the result of the genetic mix of our two parents and the experiences we have undergone in the physical world. We are also a reflection of our soul, the part of us that is the distilled essence of our previous experience in a number of earthly lives plus our spiritual experience and our actual quality or individual character originally bestowed by God.
The soul itself remains aloft in the higher worlds while it sends down a part of itself into this world, clothed in mental, emotional and physical forms. We are not normally aware of it in its full nature but we could not be aware at all were it not animating our minds with its presence. This soul has a quality. It is not just consciousness but a kind of consciousness with its own nature. It is the soul that drives this man to become a painter or that woman to become a writer, and it is the soul that largely determines the level of achievement of which each person will be capable. The story is more complicated than that because nature and nurture, conventionally understood, also have their part to play, and there is the important matter of karma or spiritual destiny to consider. Not all of the soul may be allowed to come through so that the individual may learn needed lessons. But we can still reasonably assume that those who are great artists or scientists or called to sainthood or excel in any particular field achieve what they do because of the evolution of their souls, their above average development.
Even if reincarnation is not accepted we must consider the fact of the pre-mortal existence of the soul and understand that the quality of any individual soul will have a bearing on its expression in this world. I do think it is a mistake of Christianity that it has neglected this aspect of spiritual reality. It is the soul that animates the physical form created by (or by means of) the parents. It expresses itself through that form and, though limited by the nature of that form, is a strong determining factor in what sort of person we are.
There is then this third aspect to a human being. There is the product of the parental genetic admixture. There is the conditioning of personal experience. And then there is the soul, the spiritual factor behind each individual. In many ways this is the most important.
The soul is like a light that shines through the two lenses of nature and nurture. If a human being had no spiritual pre-existence, it could not be born in this world.
N.B. I don't think the idea of reincarnation negates the element of choice that is a critical factor for all souls, the choice to turn to or away from God. That choice is one of the major reasons for a soul to be born in this world. It may be, though, that a definitive choice is put off until the individual has developed self to the point at which a truly free and intelligent decision can be made - one way or the other. But this is probably the subject for another post.