Not My Real Father

Father: "That's great, son. Who is she?"

Son: "It's Tina, the neighbor's daughter."

Father: "Ohhh, I wish you hadn't said that. I have to tell you something, son, but you must promise not to tell your mother. Tina is actually your sister."

The boy is naturally bummed out, but a couple of months later:

Son: "Daddy, I fell in love again, and she is even hotter!"

Father: "That's great, son. Who is she?"

Son: "It's Peny, the other neighbor's daughter."

Father: "Ohhhh, I wish you hadn't said that. Peny is also your sister."

This went on a couple of times, and the son was so mad, he went straight to his mother crying.

Son: "Mum, I am so mad at Dad! I fell in love with six girls, but I can't date any of them because Daddy is their father!"

The mother hugs him affectionately and says:

"My love, you can date whoever you want. Don't listen to him. He is not your father!"