"Adults and parents are often called upon in our society to set limits and guidelines for precocious and demanding children. It is in the overall best interests of our children to make participation in a full marathon an adult activity, reserved only for those 18 years of age and above. Ample number of opportunities exist after eighteen years of age to participate in this exhilarating experience of marathon running. "
 International Marathon Medical Director's Association
http://aims-worldrunning.org/articles/Children&Marathoning.pdf