Gene defects are horrific, they are amongst the worst kinds of diseases that people have. Many children die of genetic defects. A few of them like mitochondrial diseases do not always kill people but they often have major effects on the central nervous system. They are deeply unpleasant, and there is no question that if we could avoid these diseases, if we could prevent them or treat them more effectively, we should do so. However, doing genetic modifications to “fix” an issue or trying to prevent one genetic disease, we are most likely to cause another genetic problem. There a few experiments done in animals to try to fix mitochondria issues. There is one specific experiment that caught my attention when doing this research; the PEPCK mouse