One of my colleagues has a coffee mug that I think summarizes the whole genes vs. environment debate pretty well: “Nature or nurture, either way it’s your parents’ fault.” Cheeky coffee mugs aside, one of the enduring legacies that our parents give us is their DNA. We know that genes influence all sorts of outcomes—how tall we are, how much we weigh, the color of our eyes, and our likelihood of developing certain diseases and disorders. But, it was only about 25 ye…