This taboo against mentioning one's parent's or grandparent's name was a very ancient custom which sometimes produced embarrassing results. It is articularly irritating when personal names of fathers happen to be very common words.

不称父母与祖父母的名讳，在中国是很古老的风俗，有时候十分麻烦，尤其父亲的名字是很普通的字时为甚。