In the city directories usually only the man and wife, if he had one, were the only ones listed. Sometimes children were listed, but NOT with the parent(s) and only when the child was about 16 to 18 years old and beside their name it will say "student". To find any possible children in that age range for someone you find in the directories, you need to look for the surname and then all people with the same address. By looking for a surname and then going down the list and finding all persons listed at the same address, you can find parents, brothers, sisters, aunts, etc. that are related. The directory does not actually say, sister, brother, mother, aunt, etc. but after getting all names for the same address you can then determine relationships by checking the censuses or death obits, etc. Usually people with the same surname living in the same house are related somehow.