<P> Although the song continues to mention that both the narrator's wife and stepdaughter had children by the narrator and his father, respectively, the narrator actually becomes "his own grandpa" once his father marries the woman's daughter . </P> <Ul> <Li> The narrator marries the older woman . <Ul> <Li> This results in the woman's daughter becoming his stepdaughter . </Li> </Ul> </Li> <Li> Subsequently, the narrator's father marries the older woman's daughter . <Ul> <Li> The woman's daughter, being the new wife of the narrator's father, is now both his stepdaughter and his stepmother . Concurrently, the narrator's father, being his stepdaughter's husband, is also his own stepson - in - law . <Ul> <Li> The narrator's wife, being the mother of his stepmother, makes her both spouse and step - grandmother . <Ul> <Li> The husband of the narrator's wife would then be the narrator's step - grandfather . Since the narrator is that person, he has managed to become his own (step - step) grandfather . The "step - step" concept applies because the step - father of your step - mother would be your step - step - grandfather, making a "double step" event possible . </Li> </Ul> </Li> </Ul> </Li> </Ul> </Li> </Ul> <Li> The narrator marries the older woman . <Ul> <Li> This results in the woman's daughter becoming his stepdaughter . </Li> </Ul> </Li> <Ul> <Li> This results in the woman's daughter becoming his stepdaughter . </Li> </Ul>

Who sang the song i am my own grandpa