A primary teacher explains to her class that she is a Rangers fan. She asks her students to raise their hands if they, too, are Rangers fans. Everyone in the class raises their hand except one little girl. The teacher looks at the girl with surprise and says, "Mary, why didn't you raise your hand?"
"Because I'm not a Rangers fan," she replied.
The teacher, still shocked, asked, "Well, if you are not a Rangers fan, then who are you a fan of?"
"I am a Celtic fan, and proud of it," Mary replied.
The teacher could not believe her ears.
"Mary, why, pray tell, are you a Celtic fan?"
"Because my mum is a Celtic fan, and my dad is a Celtic fan, so I'm a Celtic fan too!"
"Well," said the teacher in an obviously annoyed tone, "that is no reason for you to be a Celtic fan. You don't have to be just like your parents all of the time. What if your mum was a prostitute and your dad was a drug addict, what would you be then?"
"Then," Mary smiled, "Then I'd be a Rangers fan."