Before I began reading up on fathers and their influence on future generations, I had a high-school-biology-level understanding of how a man passes his traits on to his child. His sperm and the mother's egg smash into each other, his sperm tosses in one set of chromosomes, the egg tosses in another, and a child's genetic future is set for life. Physical features: check. Character: check. Cognitive style: check. But the pathways of inheritance, I've learned, are subtler and more varied than that. Genes matter, and culture matters, and how fathers behave matters, too.
Lately scientists have become obsessed with a means of inheritance that isn't genetic but isn't nongenetic either. It's epigenetic. "Epi," in Greek, means "above" or "beyond." Think of epigenetics as the way our bodies modify their genetic makeup. Epigenetics describes how genes are turned on or off, in part through compounds that hitch on top of DNA — or else jump off it — determining whether it makes the proteins that tell our bodies what to do.
In the past decade or so, the study of epigenetics has become so popular it's practically a fad. Psychologists and sociologists particularly like it because gene expression or suppression is to some degree dictated by the environment and plays at least as large a role as genes do in the development of a person's temperament, body shape and predisposition to disease. I've become obsessed with epigenetics because it strikes me as both game-changing and terrifying. Our genes can be switched on or off by three environmental factors, among other things: what we ingest (food, drink, air, toxins); what we experience (stress, trauma); and how long we live.
Image: Father and son, via Shutterstock