The boy is naturally bummed out, but life goes on. A couple of months later…
Son: “Daddy, I fell in love again and she is even hotter!” Father: “That’s great son. Who is it?” Son: “It’s Angela, The other neighbor’s daughter.” Father: “Oh, I wish you hadn’t said that. Angela is also your” sister.
This went on couple of times and the son was so mad, he went straight to his mother crying.
“Mom I am so mad at dad! I fell in love with six girls but I can’t date any of them because dad is their father!”
The mother hugs him affectionately and says: “My love, you can date whomever you want. He isn’t your father”