At what point is life created? Is it at the time of birth or egg fertilization or at some stage in-between?
All three are possible. A soul can come at the time of conception, or in the fifth month, and in some rare cases, at the time of birth also.
This is all called the secret of birth, and we are not supposed to speak on them. One of the five great secrets – the secret of birth, the secret of death, these are all not to be discussed too much. However, you can explore it; you can go deep in meditation to explore it.