Before gastrulation, a human embryo can split into two embryos (identical twins) or two embryos can merge to become one (tetragametic chimerism). If a human embryo is a human person with a soul from the moment of conception, is a new human person and soul created when that embryo splits in two? Which of the two embryos is the same as the one that existed before - or is neither one the same and did the previous ensouled embryo die? As for a tetragametic chimera formed by the merging of two embryos (usually non-identical twins), does one of the two ensouled embryos die in this process? Is the resultant chimera embryo the same as one of the two that merged to create it? If so, which one? Or is it a different person and did the two ensouled embryos that merged to create it die in the process?
Or, can our understanding of human personhood allow one human person to split into two different human persons without either resultant human person being the same as the preceding one person but also without the death of the preceding one person? Can our understanding of human personhood allow two human persons to merge to become one human person different from either preceding person but without the death of either preceding person?