Is this a true? You should use garlic with pork and ginger with beef and never vice versa? "You should use garlic with pork and
  ginger with beef and never vice versa."


This is coming from my dad who says that fact has been handed down from generations and generations of Chinese cooking.  He says if I mix it (i.e. cook pork with ginger and beef with garlic), there will be an unpleasant taste.  Maybe he's just exaggerating, I'm not sure.  Do you think there is any truth to this saying?
Whether or not it's a good idea is subjective, but the Chinese seem to break that rule a lot!  For example, Northeastern Chinese sweet and sour pork (guō bāo ròu) is characterized by an intense ginger flavor.  The Sichuan classic twice cooked pork (huí guō ròu) calls for boiling the pork with ginger.  A common condiment for beef dishes/sauces is black bean garlic paste (蒜蓉豆豉酱).  Perhaps this saying is associated with a specific Chinese regional cuisine?