There were few aspects of my childhood as predictable as the subject of our dinner conversations. The discussion invariably gravitated to the topic of na- ture versus nurture, with the point being that all one is springs from his or her environment. As a product of my upbringing, I came to share this belief. Another fundamental lesson from my social psychologist father concerned the importance of rigorous demonstration of evidence that satisfied the high- est of scientific standards. For much of my career as a social scientist, these two values rarely, if ever, generated dissonance. But that has changed. The last several years have seen a dramatic rise, across the social sciences, in ap- proaches that ground themselves in the fundamentals of human biology, including physiology and genetics.