The capability of a sex cell with 46 chromosomes (ovum that hasn't matured fully, to reduce its chromosome complement to 23) to be stimulated into dividing is more than just that cell reproducing itself, it is that cell reproducing the individual human from whom the cell was removed!
At the moment when cell division in a conceptus begins, the conceived individual human loses, with each cell division and subsequent division, some capability to build the broadest number of tissue and organ categories. That is an important distinction to note, as the difference between average somatic cells and sex cells. It is the reason why theoretically, two sperm could be fused (each has 23 chromosomes) to form a conceptus and thus an alive embryo. It is also the reason the technician could not use two kidney cells or two liver cells or two glial cells, or even coax one of those cells to begin the differentiation journey that builds the organs and organ systems of an individual human life.