" But what if our experiences of being bullied did a lot more than just saddle us with some serious psychological baggage? Well, to answer that question, a group of researchers from the UK and Canada decided to study sets of monozygotic “identical” twins from the age of five. Besides having identical DNA, each twin pair in the study, up until that point, had never been bullied. You’ll be glad to know that these researchers were not allowed to traumatize their subjects, unlike how the Swiss mice were handled. Instead, they let other children do their scientific dirty work. After patiently waiting for a few years, the scientists revisited the twins where only one of the pair had been bullied. When they dropped back into their lives, they found the following: present now, at the age of 12, was a striking epigenetic difference that was not there when the children were five years old. The researchers found significant changes only in the twin who was bullied. This means, in no uncertain genetic terms, that bullying isn’t just risky in terms of self-harming tendencies for youth and adolescents; it actually changes how our genes work and how they shape our lives, and likely what we pass along to future generations. "

― Sharon Moalem , Inheritance: How Our Genes Change Our Lives—and Our Lives Change Our Genes