The possibility that parental life experiences and environmental exposures influence mental and physical health across generations is an important concept in biology and medicine. Evidence from animal models has established the existence of a non-genetic mode of inheritance. This form of heredity involves transmission of the effects of parental exposure to the offspring through epigenetic changes in the germline. Studying the mechanisms of epigenetic inheritance in humans is challenging because it is difficult to obtain multigeneration cohorts, to collect reproductive cells in exposed parents, and to exclude psychosocial and cultural confounders. Nonetheless, epidemiological studies in humans exposed to famine, stress/trauma, or toxicants have provided evidence that parental exposure can impact the health of descendants, in some cases, across several generations. A few studies have also started to reveal epigenetic changes in the periphery and sperm after certain exposures. This article reviews these studies and evaluates the current evidence for the potential contribution of epigenetic factors to heredity in humans. The challenges and limitations of this fundamental biological process, its implications, and its societal relevance are also discussed.
Keywords: disease risk; epigenetic; exposure; humans; inheritance; intergenerational; offspring; parents; transgenerational.