Although many of the questions asked about DNA and the molecular structure of the gene have been answered, according to recent research, not everything consists of genes. Common genetic analysis in the fields of biology and medicine remains insufficient. Environmental factors can cause changes in gene expressions concerning the whole process from embryo formation to the last moment of life. Gene expressions manifest themselves differently in each cell. The branch of science that examines the external sources that cause genes to be active or passive is called "epigenetics" which literally means "above genetics". Epigenetic changes occur without causing a change in the base sequence, are passed on to subsequent generations, and are often reversible. Epigenetic signs reveal the mechanical link between environment, nutrition, and diseases. Epigenetics is important in the development of human and public health, benefiting from health services, understanding the genetics of complex traits, and determining the social position of the human being. The current secondary education program needs to be updated in order to educate scientifically literate citizens who are compatible with the science of the 21st century. Epigenetics is as important a field of study as genetics. This is a review of the literature on epigenetics. It has been determined how the teaching of genetics, which includes epigenetics, is included in the curriculum in different countries. Based on all these, the reasons why epigenetics should be included in the secondary education curriculum are explained in this study.