This study investigates the long-term epigenetic effects of prenatal exposure to famine during the Dutch Hunger Winter in 1944–45. The researchers found that individuals exposed to famine during periconception had significantly lower DNA methylation of the *IGF2* gene, a key regulator of growth and development, compared to their unexposed, same-sex siblings. This association was specific to periconceptional exposure, suggesting that very early stages of mammalian development are crucial for establishing and maintaining epigenetic marks. The findings provide empirical support for the hypothesis that early-life environmental conditions can cause persistent epigenetic changes in humans that influence adult disease risk. The study also highlights the importance of assessing maternal lifestyle and embryo growth during early development to better understand the developmental origins of health and disease.This study investigates the long-term epigenetic effects of prenatal exposure to famine during the Dutch Hunger Winter in 1944–45. The researchers found that individuals exposed to famine during periconception had significantly lower DNA methylation of the *IGF2* gene, a key regulator of growth and development, compared to their unexposed, same-sex siblings. This association was specific to periconceptional exposure, suggesting that very early stages of mammalian development are crucial for establishing and maintaining epigenetic marks. The findings provide empirical support for the hypothesis that early-life environmental conditions can cause persistent epigenetic changes in humans that influence adult disease risk. The study also highlights the importance of assessing maternal lifestyle and embryo growth during early development to better understand the developmental origins of health and disease.