Matt Ridley: How Dickensian childhoods leave genetic scars

Being maltreated as a child can perhaps affect you for life. It now seems the harm might reach into your very DNA. Two recently published studies found evidence of changes to the genetic material in people with experience of maltreatment. These are the tip of an iceberg of discoveries in the still largely mysterious field of "epigenetic" epidemiology-the alteration of gene expression in ways that affect later health.

According to standard theory, genes aren't supposed to change, so you can pass them on to generations untainted by your own mistakes. It now seems they can at least acquire marks of experience during life, affecting how much they are "expressed."