Epigenetics entails studying the mechanisms through which cells regulate and control gene activity without altering the sequence and structure of the DNA. It involves studying factors beyond the genetic code, such as an individual's behavior, exercise, and the environment. These factors result in DNA changes and modifications that determine whether genes are turned on or off. Epigenetic modification is composed of three main processes: DNA methylation and demethylation, histone alteration and non-modification, and coding RNA silencing. Epigenetic modifications also result in the growth and advancement of various illnesses in multicellular organisms, such as cancers, autoimmune diseases, diabetes, and neurological disorders such as Fragile X syndrome, Huntington's, Alzheimer's, Parkinson's disease, and schizophrenia. Since reversible genetic modifications cause these disorders, epigenetic treatments can counter them. These treatments mainly alter DNA methylation and Histone acetylation. Though coding DNA was only two percentage, the majority of the DNA was regulatory DNA, which changed the genetic code due to environmental pressures. These changes are very useful, particularly the regularization of organ-specific functions by suppressing other functions in specific organs. But in certain situations, these changes may be harmful. For example, stress due to urbanization may transfer to future generations. In the descendants of Holocaust survivors that result in a marked increase of post-traumatic stress disorder, depression, and obesity, all resulting from differential methylation of the FKBP5 gene. The majority of preterm deliveries, which were pushed by nature, will have obesity and hypertension, which will trnsver in the form of epigenitics to future generation to decrease the lifespan of human. This may be a single step in the future evaluation process.