The study by Pembrey et al. investigates the transgenerational effects of paternal smoking and food supply on offspring and grandchild health outcomes. Using the Avon Longitudinal Study of Parents and Children (ALSPAC) and historical records from the Överkalix cohort in northern Sweden, the researchers found that early paternal smoking is associated with increased body mass index (BMI) in sons at 9 years of age, but not in daughters. Sex-specific effects were also observed in the Överkalix data, where paternal grandfather's food supply was linked to the mortality risk of grandsons, while paternal grandmother's food supply was linked to the mortality risk of granddaughters. These transgenerational effects were observed during the slow growth period (SGP) and fetal/infant life but not during puberty. The study concludes that sex-specific, male-line transgenerational responses exist in humans and hypothesizes that these transmissions are mediated by the sex chromosomes, X and Y. These findings add a new dimension to the study of gene-environment interactions in development and health.The study by Pembrey et al. investigates the transgenerational effects of paternal smoking and food supply on offspring and grandchild health outcomes. Using the Avon Longitudinal Study of Parents and Children (ALSPAC) and historical records from the Överkalix cohort in northern Sweden, the researchers found that early paternal smoking is associated with increased body mass index (BMI) in sons at 9 years of age, but not in daughters. Sex-specific effects were also observed in the Överkalix data, where paternal grandfather's food supply was linked to the mortality risk of grandsons, while paternal grandmother's food supply was linked to the mortality risk of granddaughters. These transgenerational effects were observed during the slow growth period (SGP) and fetal/infant life but not during puberty. The study concludes that sex-specific, male-line transgenerational responses exist in humans and hypothesizes that these transmissions are mediated by the sex chromosomes, X and Y. These findings add a new dimension to the study of gene-environment interactions in development and health.