Mordechai's rebbe met up with Dovid today in yeshiva and told over the following conversation he had had today with Mordechai:
Mordechai: Is it okay to ask a rebbe when his birthday is?
Rebbe: The Torah doesn't say you can't but it's not so nice to ask older people because it's considered a private question.
Rebbe: Why? Does it make a difference?
Mordechai: Not really. I just wanted to know your birthday so I could tell my mother to bake a cake.