When the sperm enters the ovum it finds food. Interwining the two parent’s DNA strands, building someone entirely new. We’re all parameciums at that point. Sex doesn’t occur until the first cell division. I theorize that 5 stem cells are the first cell divisions. Some of those divisions may be: brain, pineal (or perhaps other similar glands), bone, organs, and nervous system (or perhaps muscle).
So modifying the DNA in the stem cells might work, but would likely create conflict with that original paramecium. I wonder if the original paramecium is contained in the pineal itself. Locked away until emotional trauma is entirely healed.
When do we ever get back to that original paramecium (self)?