I read some magazine and found this:
"It's a tossup whether father or son is the bigger wise guy."
Is "father or son" an institutionalized expression so that an article (like "a" or "the") is not necessary?
This optional omission of the articles is very common where two nouns with some sort of relationship between them are joined by and or or. Thus we have, for example:
Mother and/or child
Doctor and/or patient
Pen and/or pencil.
Sometimes the relationship is one of identity: wife and mother.
NOT A TEACHER