It always puzzled me. Why is it that if you let loose a group of young children in a toy store, boys would gravitate to the toy gun section, girls to the dolls. Even when toy guns are not available, boys will point their fingers to simulate a gun when playing cops and robbers.
Let me hasten to add that there is no evidence that boys playing with toy guns leads to increase in violent behavior in later years. Still, is there something genetic about it? Something cultural? Both?