Induced Pluripotent Stem Cells (iPSCs) show virtually all the same characteristics as embryonic stem cells manufactured by manipulating and destroying human embryos. The final test that these cells have yet to pass is whether or not they can fix a hamstrung embryo and allow it to develop into an adult made from the stem cells.
If embryonic stem (ES) cells can make any tissue in the adult body, then they should, when placed in an embryo, make any and all adult tissues. Furthermore, if placed in an embryo that cannot make adult structures, then the embryonic stem cells, if they are truly pluripotent, should take over and make the embryo. This type of test is called tetraploid complementation. It uses embryos that have four copies of each chromosome. Tetraploid embryos, those with four copies of each chromosome, can make the placenta, but not the embryo. Therefore, if embryonic stem cells are injected into tetraploid embryos, the embryos will not die. Instead the embryonic stem cells will respond to the new environment in which they were placed and make the embryonic, fetal, and adult structures. This experiment is tetraploid complementation and embryonic stem cells can do this. Can iPSCs do this? Recent data strongly argues that they can.
Qi Zhou at the Chinese Academy of Sciences in Beijing and his colleagues, Shaorong Gao at the National Institute of Biological Sciences in Beijing, and Kristin Baldwin of the Scripps Research Institute in San Diego, California, made iPSCs, injected them into tetraploid embryos, placed them into surrogate mother mice, and observed the birth of mouse pups that were genetically identical to the iPSCs that were injected into the tetraploid embryos. When these mouse pups grow to maturity, they are also fertile.
These experiments show that iPSCs have they same ability to form all the tissues of the adult human body as embryonic stem cells made from the destruction of embryos. In short we DO NOT NEED embryonic stem cells from from the corpses of human embryos to cure sick people.