Got Issues: Blame Your Grandma
The idea of the tabula rasa is all but forgotten. Advances in modern genetics have taught us that not only are we not a blank slate at birth, but we are not even simply the product of our genes. The environment interacts with our genes to shape our development, however, it is not only OUR environment that does so. Let me tell you about an early discovery that led to this knowledge. In 1944, a German-blockade to the Netherlands blocked access to food the supply to a number of individuals. Calories were severely restricted during the winter of 1944-1945. Many infants died of malnutrition and related issues. Women who were pregnant during this time also suffered a shortage of calories, and, not surprisingly, their infants were born much smaller than is typical. It appeared that these babies were small due to the reduced nutritional availability in utero. These children grew up post-blockade, and physically "caught up" with their peers in size. However, when the women from this cohort had their own children, remember, these are women of typical size and had full access to food, their babies were again much smaller than is typical. Thus, the experience of these infants' grandmothers led to these changes. These changes occurred epigenetically, such that environmental events resulted in changes in gene expression, and importantly that this occurred not only within individuals but also across generations. Their epigenetic changes programed for a calorie-restricted world.
Some may find it discouraging to realize we each carry the burden of epigenetic programming passed down from our mother or grandmother, but these changes may actually be good. You never know if you'll need those adaptations for your environment.