CarlZimmerinThe New York Times:
Scientists are investigating the epigenetics of fatherhood: how a man’s experiences can alter his sperm, and whether those changes in turn may alter his children. Credit Dann Tardif/LWA, via Corbis. A week before the operation, the man provided a sperm sample to Danish scientists. A week after the procedure, he did so again. A year later, he donated a third sample. Scientists were investigating a tantalizing but controversial hypothesis: that a man’s experiences can alter his sperm, and that those changes in turn may alter his children. That idea runs counter to standard thinking about heredity: that parents pass down only genes to their children. People inherit genes that predispose them to obesity, or stress, or cancer — or they don’t. Whether one’s parents actually were obese or continually anxious doesn’t rewrite those genes. Yet a number of animal experiments in recent years have challenged conventional thinking on heredity, suggesting that something more is at work.
In 2010, for example, Dr. Romain Barres of the University of Copenhagen and his colleagues fed male rats a high-fat diet and then mated them with females. Compared with male rats fed a regular diet, those on the high-fat diet fathered offspring that tended to gain more weight, develop more fat and have more trouble regulating insulin levels. Eating high-fat food is just one of several experiences a father can have that can change his offspring. Stress is another. Male rats exposed to stressful experiences — like smelling the odor of a fox — will father pups that have a dampened response to stress.