The term epigenetics, literally over/above the generation, was first used in print over a century ago. In biology, it is the study of changes in the phenotype (expressed physical traits) that appear without a correlated change in the DNA.
The term is now used broadly to encompass a wide variety of illnesses and behaviors that appear to have heritable links through energy and can be found in scientific literature as TTT—transgenerational transmission of trauma. It is a kind of biological memory that integrates both hereditary and environmental factors. The best known epigenetic studies are those involving PTSD parents (from the holocaust, wars and other human catastrophes) and the debilitating anxiety, depression and low stress thresholds that appear in their children over more than one generation.
Most researchers believe that there are innumerable chemical, situational, and biological triggers for epigenetic processes.