After many years, Mother and Father bring in their 5 sons to have a talk with them and get something off their chest. 

Dad says, "Come on in here and sit down, boys. 

Your mother and I have something to tell you. 

I know it's not going to be easy to hear, but your mother and I were never married."

The boys sit there, dumbfounded, heads in their hands, not knowing how to react.

After several moments in awkward silence went by, the mother, not being able to handle it any longer, says, "Well? Aren't you bastards going to say anything?"