Su Wong marries Lee Wong. The next year, the Wongs have a new baby. The nurse brings over a lovely, healthy, bouncy, but definitely a Caucasian, WHITE baby girl.
"Congratulations!' says the nurse to the new parents. "Well Mr. Wong, what will you and Mrs. Wong name the baby?"
The puzzled father looks at his new baby girl and says, "Well, two Wong's don't make a white, so I think we will name her Sum Ting Wong."