In the nineteenth century, the English polymath Francis Galton cast nature-versus-nurture in scientific terms. He envisioned a battle between heredity and experience that shapes each of us.
“When nature and nurture compete for supremacy…the former proves the stronger,” Galton wrote in 1874.
Today, scientists can do something Galton couldn’t imagine: they can track the genes we inherit from our parents. They are gaining clues to how that genetic legacy influences many aspects of our experience, from our risk of developing cancer to our tendency to take up smoking.
But determining exactly how any particular variation in DNA shapes the course of our life is proving far trickier than Galton would have guessed. There is no clean line between nature and nurture: How a particular variant acts, if at all, may depend on your environment.