Childhood sexual abuse may leave “molecular scars” on a victim’s DNA which could one day be used as evidence in court, scientists have said.

A new study found similar alterations in the activity of genes among men who had been abused in childhood.

Researchers at Harvard and the University of British Columbia (UBC) believe the discovery of the differences in a process called methylation between those who had been abused and those who had not could pave the way for a genetic test to indicate whether abuse took place.

Methylation acts as a “dimmer switch” on genes, affecting the extent a particular genes is activated or not.

Published in the journal Translational Psychiatry, the study found a distinct methylation difference between victims and non-victims in 12 regions of the men’s genomes.

In eight DNA regions, the genes of victims were dimmed by more than 10 per cent compared to non victims, and in one region the difference was 29 per cent.

Michael Kobor, professor of medical genetics at UBC, said: “Methylation is starting to be viewed as a potentially useful tool in criminal investigations - for example, by providing investigators with an approximate age of a person who left behind a sample of their DNA.