Epigenetics: A mother's diet, nutritional deficiencies, stress, and exposure to toxins during pregnancy cause 'epigenetic' changes that turn gene expression on or off in the fetus. If nutrients are insufficient during pregnancy, the baby's organs and immune system fail to develop normally, resulting in birth with a lifelong risk of metabolic and digestive diseases. In the past, Dr. Weston Price referred to this not as a genetic defect, but as 'intercepted heredity,' where the normal genetic blueprint is not expressed due to nutritional deficiencies.