What makes young people act in antisocial ways? This question is discussed from several different angles in our current issue. Delinquency is not, of course, a new phenomenon: for those interested in reading a chilling account of life in London in the early years of the last century, Cyril Burt's The young delinquent, published in 1925, is worth tracking down. Definitive answers seem as far away as ever, but the idea that delinquency might be influenced to a significant extent by genetic mechanisms is still a controversial one. Taylor et al. conducted a twin study, and found the variance in delinquent behaviour among adolescent boys and girls was associated largely with experiences that were unique to individuals. Family influences accounted for half of the remaining variance in risk less than 20% could be attributed to additive genetic factors. Their findings imply, they suggest, scope for prevention and/or intervention. On a similar topic, Hawker and Boulton ask, why is it that some children are bullied? What effect does bullying have on children's emotional adjustment? They review the history of research on this topic, going back over two decades to the pioneering studies of Dan Olweus. Using meta-analytic techniques, they conclude victims become emotionally distressed and, in particular, depressed. Clinicians should realise that children who present with emotional problems may be the victims of bullying; interventions that target either bullying or emotional distress may reduce the severity of both problems.