studies suggest the existence of transgenerational epigenetic inheritance in humans, which includes the Dutch famine of 1944–45. During the Dutch hunger winter, the offspring born during the famine were smaller than those born the year before the famine. The effects of this famine on development lasted up to two generations. Moreover, the offspring born during the famine were found to have an increased risk of glucose intolerance in adulthood. Differential DNA methylation has been found in adult female offspring who had been exposed to famine in utero, but it is unknown whether these differences in DNA methylation were passed on to their germline. It is hypothesized that inhibiting the PIM3 gene may have caused slower metabolism in later generations, but causation has not been proven, only correlation. The phenomenon is sometimes referred to as Dutch Hunger Winter Syndrome. Furthermore, the increased rates of metabolic diseases, cardiovascular diseases, and other increased risk factors to the health of F1 and F2 generations during the Dutch hunger winter is a known phenomenon called “fetal programming,” which is caused by exposure to harmful environmental factors in utero. Another study hypothesized that epigenetic changes on the Y chromosome could explain differences in lifespan among the male descendants of prisoners of war in the American Civil War. The Överkalix study noted sex-specific effects; a greater body mass index (BMI) at 9 years in sons, but not daughters, of fathers who began smoking early. The paternal grandfather's food supply was only linked to the mortality RR of grandsons and not granddaughters. The paternal grandmother's food supply was only associated with the granddaughters' mortality risk ratio. When the grandmother had a good food supply was associated with a twofold higher mortality (RR). This transgenerational inheritance was observed with exposure during the slow growth period (SGP). The SGP is the time before the start of puberty, when environmental factors have a larger impact on the body. The ancestors' SGP in this study was set between the ages of 9-12 for boys and 8–10 years for girls. This occurred in the SGP of both grandparents, or during the gestation period/infant life of the grandmothers, but not during either grandparent's puberty. The father's poor food supply and the mother's good food supply were associated with a lower risk of cardiovascular death. The loss of genetic expression which results in Prader–Willi syndrome or Angelman syndrome has in some cases been found to