The review critically examines the current state of population epigenetics. Possible mechanisms of intergenerational inheritance of epigenetic and epigenomic modifications as a condition of population epigenetics reality are examined. Special attention is paid to the role of external factors, including diet and various chemical compounds as modulators of the epigenome, and the possible inheritance of epigenetic variability characteristics under the influence of such environmental factors. The role of epigenetic mechanisms in the etiology and susceptibility to complex human diseases is considered.