Can a man’s exercise habits influence the brains of his children? Researchers at the German Center for Neurodegenerative Diseases in Göttingen, Germany, think that it can. The New York Times reports that scientists at the center divided a large group of genetically identical mice into two groups, and put one group in cages with running wheels, and one in cages with no wheels. After ten weeks, the researchers examined the brains of the mice, and found that those who had exercised had stronger neuronal connections than the mice that had remained sedentary. No surprise there. But what was surprising was the brains of those mice’s offspring. The Times reports that when active males mated with sedentary females, their offspring had stronger neuronal connections than the offspring of sedentary fathers. The young mice also learned faster and had better memories, even though they themselves did not run. The researchers were also surprised to find that levels of two microRNAs, which are known to rise in the brains of running mice and thought to foster better connections between brain cells, were not elevated in the offspring. The Times reports that none of this second generation of mice, which never exercised, had offspring with notably strong neuronal connections, suggesting that the epigenetic benefits from running ended when the running did.