How stress echoes down the generations

The effects of child abuse can last a lifetime. Neglected or abused children have a higher risk of developing all sorts of ailments as adults, including mental illnesses such as depression but also physical ones like cancer and stroke. In fact, the effects may last even longer. Emerging evidence suggests that the consequences of mistreatment in childhood may persist down the generations, affecting a victim’s children or grand-children, even if they have experienced no abuse themselves.

Exactly how this happens is not well understood. Rigorous experiments on human subjects are difficult. Scientists have therefore turned to rats and mice. But now Larry Feig of Tufts University and his colleagues have shown that psychological stress seems to cause similar changes in the sperm of both mice and men. Their study is published this week in Translational Psychiatry.

Biologists know that traits are carried down the generations by genes. Genes encode proteins, and proteins make up organisms. That is still true. But it has recently become clear that it is not the whole story. Organisms regulate the activity of their genes throughout...