Eventually in the discussion of reincarnation, the following question will almost always be asked:
How can God permit the death of innocent children?
The following excerpt from Edgar Cayce reading 262-57 is the best explanation which the Source could provide:
(Q) Does the truth, "By becoming aware in a material world was the only manner through which spiritual forces might become aware of their separation from spiritual surroundings" show that the reincarnation of those who die in childhood is necessary?
(A) As the awareness comes by separation (which is being manifested in materiality as we know it in the present), there is the necessity of the sojourning in EACH experience for the developments of the influences necessary in each soul's environ, each soul's attributes, to become again aware of being in the PRESENCE of the Father. Hence the reincarnation into this or that influence, and those that are only aware of material or carnal influences for a moment may be as GREATLY impressed as were a finite mind for a moment in the presence of Infinity. How long was the experience of Saul in the way to Damascus? How long was the experience of Stephen as he saw the Master standing - not sitting, STANDING? How long was the experience of those that saw the vision that beckoned to them, or any such experience? When one considers the birth of a soul into the earth, the more often is the body and the body-mind considered than the soul - that is full-grown in a breath. For, did the Father (or Infinity) bring the earth, the worlds into existence, how much greater is a day in the house of the Lord - or a moment in His presence - than a thousand years in carnal forces? Hence a soul even for a flash, or for a breath, has perhaps experienced even as much as Saul in the way.
To condense this down... Life in this material realm, for the time that it takes for even one breath, can be equated to a finite human mind grasping infinity, as is also known by the Hindu term, Samadhi.
Such a short time span for incarnation is a part of the paln for that particular soul, in order to learn whatever divine lesson that soul is choosing to experience for itself, and perhaps to offer the opportunity for the parents, family, and friends to also learn a lesson.