Stem cells are formed by the union of sperm and ovum, first forming a cell and then it divides into many more cells in stages and later on those cells gradually transform into skin and other organs. These early embonic cells are called stem cells. Transformation of this organ is quite complex and scientists have been trying to understand this process for the last 40 years. Since these stem cells transform into organs , if we can program them properly, we can make organs from them. Based on this idea, many scientists have been able to show some successful experiments. Memory Cells The part of the brain that does the job of storing memories is called the hippocampus or memory center. However, this memory cell has not been used since the age of 13.