In the US in the current era, morbidity and mortality due to gun-related injuries constitute a major public health problem. Children are affected by the gun hazard as survivors of gun victims and as victims of gun homicides, suicides and unintentional injuries. US boys also are involved with guns in childhood play: toy guns early and non-powder firearms later. Toy guns cause some injuries to very young boys, are more dangerous than is generally recognized, and promote aggressive play. Non-powder firearms cause numerous injuries, including severe ones, to school-aged boys. Neither type of 'gun' is regulated. The possible developmental effects of gunplay in childhood are discussed. It is hypothesized that boys in the US develop a reliance on guns in part as a result of childhood gunplay, and that alterations in patterns of childhood gunplay might help to reduce the US gun hazard. There is need for research and debate concerning this possibility.