There is a reasonably strong probability that each Earthly human being is a soul-entity passing through space and time. A recent post of mine discussed the role of reincarnation in the process, whereby a soul-entity adopts a human body sequentially.
A close friend of mine has raised with me a question which was asked by an elderly friend (an atheist) about 50 years ago. Since the human population is growing rapidly, would there be enough soul-entities?
My response is: Why assume that the number of souls is limited? In economic theory, in spite of its limitations, there used to be a premise that supply would rise to meet demand.
Whether the supply of souls will rise to meet bodily demand will require us to identify the source of souls; and to decide why there may be bottlenecks in the supply process. How can we know?
An alternative approach is whether human bodies are created to meet an independent creation of souls. Our proclivity for procreation is well documented.
Soul creation and its role is indeed a fascinating challenge – at least to those of us who believe that there is meaning in human existence. In the complex mesh of a universe in which everything seems to be connected, what indeed is our role?
Hindu metaphysics offers an explanation of the origin of souls and the implicit role of the reincarnation process. Because of repeated rebirths, each periodic increase of human bodies will give a measure of the extra souls needed (or available).
As to when a soul enters a human body is a matter of contention, muddled significantly by competitive religions (whose leaders should really know better) claiming to own a sole path to Nirvana/Heaven and the accoutrements necessary to access it; or seeking control (to what spiritual extent?) of their believers. The pathos of ecclesiastical ambition!
I doubt if the Afterlife (or Recycling Station) has separate mansions or even rooms defined by religious affiliation. The futility of cemeteries on Earth separating empty bodies (the souls having departed) by religious sect is a reminder of the folly of seeking to keep separate those humans seeking the Divine, but who are travelling along separate routes, perhaps by necessity.
Ultimately, we are indeed one – in origin and through fusion on return.