There are few data on youth marathon runners and the most commonly asked questions of "can children run marathons?" and "what are the health consequences?" remain unanswered. Expert opinion is split with regard to running this distance at a young age. There have been many thousands of finishers <18 years old at the Los Angeles Marathon in an organised programme for youth running and nearly 300 finishers in at the Twin Cities Marathon. The youngest child in these data sets was 7 years old. There has not been any significant medical injury at these events. Children who choose of their own accord to participate in marathon training should be allowed to do so as long as their social, academic, psychological and physiological development is not disrupted. Follow-up studies of these young runners would help evaluate the long-term health consequences of long distance running and shape future recommendations.