Why Do They Do These?

During their Sunday lunch, John’s mother observed that he was absent mindedly smiling to himself. “A penny for your thoughts,” she said. And with a broad smile on his face, John announced, "Dad, Mum, I have found myself a wife. She is Agnes, the most beautiful girl in our neighbourhood.” And both parents chorused, “That is great news, son.” After lunch, John’s father took him to his study, sat him down and said, “Though your mother is a wonderful wife and mother, she has never offered me much excitement in the bedroom, so I used to fool around with other women a lot. Son, I'm afraid you can't marry Agnes because she is actually your half-sister.”

It took John about nine months to get over the shock. Then he met and started dating Josephine; and later brought her home to meet his parents.  After the introduction, his father insisted on another private conversation and broke the sad news. "Son, I'm awfully sorry about this. Josephine is your half-sister too.” Angrily, John went and complained to his mother saying, "Mum, Dad has done so much harm to my love life. I guess I'm never going to get a wife around here. Every time I fall in love, he tells me the girl is my half-sister." But his mother chuckled, shook her head and said, "Don't pay any attention to what he says. He's not really your father."