Shinya Yamanaka succeeded in making iPS cells in 2006. ES cells already existed as universal cells before iPS cells were created.
However ES cells have an ethical problem. Since ES cells are cells that have been taken out by breaking embryos, they are thought to be a research to pick up the buds of life, and criticism is also persistent.
And another problem is the refusal to recognize non self. IPS cells solved the problem of such ES cells.
Because iPS cells are created by removing the differentiated cells from the body, no ethical problems arise. In addition, because the cell of the patient itself can be used, no rejection reaction occurs.

