You may or may not know the word "kunya" but in one way or another you probably have already heard of a kunya. Educational materials on Arab culture or the Middle East will teach you that kunyas are honorific names/titles used by Arabs. What is generally taught is that someone named "Abu Umar" is the father of a child named Umar. "Umm Umar" would be the mother of Umar. Meanwhile an Ibn Thahr is the son of a Thahr.
All Catholicgauze can say is that is how the system was meant to work but no longer does (or in my sleep-deprived thinking, "Lies! Horrible Lies!). In today's modern Middle East the kunya has devolved into nicknames that can be used in place of true birth names on almost anything expect official government documents. People will take a kunya to tie themselves with popular historical figures, their profession, even favorite sports stars.
What is truly something else is one can have a kunya for certain situations. For instance, your friends may know you as "Abu Ahmad" after your son but your your co-workers may know you as "Abu Jindal" after the local soccer star. Surprisingly your family may not know you use the kunya Abu Jindal. So a co-worker could call your home, ask for an "Abu Jindal," and be told no one by that name lives there. Your co-workers may not know your true name so any attempts to reach you would end in vain right then and there.
Catholicgauze has encountered this problem already and plans on many more name searches. I can only imagine how people who live in the Middle East manage to work around this kunya problem.