There was a middle aged couple that had two stunningly beautiful teenage daughters. The couple decided to try one last time for the son they always wanted. After months of trying, the wife finally got pregnant and sure enough delivered a healthy baby boy nine months later. The joyful father rushed into the nursery to see his new son. He took one look and was horrified to see the ugliest child he had ever seen. He went to his wife and told her there was no way he could be the father of that child.
"Look at the two beautiful daughters I fathered!" Then he gave her a stern look and asked, "Have you been fooling around on me?"
The wife just smiled sweetly and said, "Not this time!"