One Sunday morning George burst into the living room with a huge grin on his face.
“Dad! Mom! I have some great news for you! I am getting married to the most beautiful girl in town. She lives only a block away and her name is Susan!”
After dinner, George’s dad took him aside, “Son, I have to talk with you. Look at your mother. She and I have been married 25 years, she’s a wonderful wife and mother, but, she has never offered much excitement in the bedroom, so I used to fool around with women a lot. Susan is actually your half-sister, and I’m afraid you can’t marry her.”
George was broken-hearted but had to accept the bad news.
After eight months he eventually started dating girls again. A year later he came home and very proudly announced, “Diane said yes! We’re getting married in June!”
Again his father insisted on another private conversation and broke the sad news. “Diane is your half-sister too, George. I’m awfully sorry about this.”
Hearing this, George was livid. He decided to go find his mother and fill her in. He corners her in the garden and complains, “Dad has done so much harm. I guess I’m never going to get married. Every time I fall in love, Dad tells me the girl is my half-sister.”
His mother cracks up laughing, “Don’t pay any attention to what he says. He’s not really your father.”