2 . Biology is making it clearer that a man’s health and well-being have a measurable impact on his future children’s health and happiness. This is not because a strong, responsible man has a greater ______ of being a good dad—or not only for that reason—or because he’s probably got good genes. Whether a good man’s genes are good or bad(and whatever “good” and “bad” mean in the context)，his children’s bodies and minds will reflect ______ choices he has made over the years, even if he made those choices ______, he ever imagined himself strapping on a baby Bjorn.

Doctors have been telling men for years that smoking, drinking and recreational drugs can lower the ______ of the sperm(精子). What doctors should probably add is that the health of unborn children can be affected by what and how much men eat; the toxins(poisonous substances)they ______, the traumas(unpleasant experiences)they endure, their poverty or powerlessness; and their age at the time of conception(怀孕). ______, what a man needs to know is that his life experience leaves ______ traces on his children. Even more astonishingly, those children may pass those traces along to their children.

Lately scientists have been obsessed with(着迷于)a means of ______ that isn’t genetic but isn’t non-genetic 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 ______ genes are turned on or off, in part through compounds that get on top of DNA—or else jump off it—______ 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 ______ that it is practically a craze. Psychologists and sociologists particularly like it because gene expression or suppression(抑制)is ______ affected by the ______ and plays at least as large a role as genes do in the development of a person’s characteristics, body shape and tendency to disease. I’ve become obsessed with epigenetics because it ______ 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 ______(stress, trauma)，and how long we live.