If the child was not in custody, it is perfectly legal for the police to question a child without their parent(s) present.  This typically happens when an officer has a reasonable belief that a minor has violated the law.  In that instance, the officer can detain the minor to conduct an investigation and during this initial detention, police are not required to let a minor call his parents.   Minor's have the right to call their parents if the minor is arrested and taken to the police station or juvenile hall.  The minor also has the right to have their parents present during a custodial interrogation that implicates the minor's Miranda rights.   For example, if a child is questioned at school it has successfully been argued that this can constitute custody.Note:  And as with anyone, regardless of age, if in custody and not given the Miranda warning no statements made by them can be used later.