The song lyrics to "I am My Own Grandpa" are whimsical and fictitious, of course. Or are they? Consider the following true story:
At age 47, the Rolling Stones' bassist, Bill Wyman, began a relationship with 13-year old Mandy Smith, with her mother's blessing. Six years later, Bill and Mandy were married, but the marriage only lasted a year. Not long after, Bill's 30-year-old son from a former marriage, Stephen, married Mandy's mother, age 46. That made Stephen a stepfather to his former stepmother. If Bill and Mandy had remained married, Stephen would have been his father's father-in-law and his own grandpa.