the old saw-- Your son is your son, till he takes a wife, but your daughter is your daughter all her life. come to mind..

i think sons and daughters often have very different relationships with parents (and in laws) --but that said, women do often call other women daughters (she is like a daughter to me! is one of the best compliments a woman can pay to another woman) but its a rare thing.

it is true that son can be any child (listen to me, son (or sonny boy!) or natural child.. and it can be a ToE too...

daughter is used less frequently (more often, sister is used--but since biologically sisters are closer related than daughters,--it might be woman have several relationship words to express affection..