Does a parent-child relationship have an equivalent to the word "sibling"?
Brother to brother: "We are brothers. We are siblings"
Son to father: "We are ________."
I do not know of a word in English to express parent-child relations like that other than in terms of one to the other (i.e. "you are my father; I am your son"). The closet I can think of is using the family name ("we are Lannisters").