The effects of stress may be passed down the generations Dennis Kunkel/SPL

Childhood trauma leaves a lasting mark – in your sperm. A study of 28 men has found that those who had difficult childhoods carry chemical clues to their past in their sperm, and these may be passed down to their sons.

Previous studies have found that stress can affect the health and behaviour of mice, and that these changes seemed to be passed down to their offspring, possibly through their sperm. Such transgenerational changes have been controversial. While we know that fathers who smoke tend to have heavier sons …