Rethinking evidence for epigenetic inheritance in human research

In multicellular organisms, epigenetic inheritance is a process by which traits induced by life experiences or environmental factors in a parent are passed to offspring without involving changes in the DNA sequence, but rather in the epigenome. While epigenetic inheritance is evident in many species, from plants to rodents, it remains unproven in humans because of biological barriers, methodological complexity, and the difficulty of disentangling environmental from social and genetic factors. The unique human context of prolonged parental care, as well as cross-generational cultural and societal effects, compounds these difficulties and highlights the need for clear criteria to assess epigenetic inheritance claims. This article aims to help the field move from cataloging biological markers to conducting rigorous human research by clarifying key concepts and defining testable criteria as a guiding framework.