spouse(X, Y) :- married(X, Y).
husband(X, Y) :- male(X), married(X, Y).
wife(X, Y) :- female(X), married(X, Y).
father(X, Y) :- male(X), parent(X, Y).
mother(X, Y) :- female(X), parent(X, Y).
sibling(X, Y) :- father(Z, X), father(Z, Y),
mother(W, X), mother(W, Y), not(X = Y).
brother(X, Y) :- male(X), sibling(X, Y).
sister(X, Y) :- female(X), sibling(X, Y).
grandparent(X, Z) :- parent(X, Y), parent(Y, Z).
grandfather(X, Z) :- male(X), grandparent(X, Z).
grandmother(X, Z) :- female(X), grandparent(X, Z).
grandchild(X, Z) :- grandparent(Z, X).
grandson(X, Z) :- male(X), grandchild(X, Z).
granddaughter(X, Z) :- female(X), grandchild(X, Z).
ancestor(X,Y) :- parent(X,Y).
ancestor(X, Y) :- parent(X, Z), ancestor(Z, Y).
child(Y, X) :- parent(X, Y).
son(Y, X) :- male(Y), child(Y, X).
daughter(Y, X) :- female(Y), child(Y, X).
descendent(Y, X) :- ancestor(X, Y).
auntoruncle(X, W) :- sibling(X, Y), parent(Y, W).
auntoruncle(X, Z) :- married(X,Y), sibling(Y,W), parent(W,Z).
uncle(X, W) :- male(X), auntoruncle(X, W).
aunt(X, W) :- female(X), auntoruncle(X, W).
cousin(X, Y) :- parent(Z, X), auntoruncle(Z, Y).
nieceornephew(X, Y) :- parent(Z, X), sibling(Z, Y).
nephew(X, Y) :- male(X), nieceornephew(X, Y).
niece(X, Y) :- female(X), nieceornephew(X, Y).
greatgrandparent(X, Z) :- parent(X, Y), grandparent(Y, Z).
greatgrandfather(X, Z) :- male(X), greatgrandparent(X, Z).
greatgrandmother(X, Z) :- female(X), greatgrandparent(X, Z).
greatgrandchild(X, Z) :- child(X, Y), grandchild(Y, Z).
greatgrandson(X, Z) :- male(X), greatgrandchild(X, Z).
greatgranddaughter(X, Z) :- female(X), greatgrandchild(X, Z).
parentinlaw(X, Y) :- married(Y, Z), parent(X, Z).
fatherinlaw(X, Y) :- male(X), parentinlaw(X, Y).
motherinlaw(X, Y) :- female(X), parentinlaw(X, Y).
siblinginlaw(X, Y) :- married(Y, Z), sibling(X, Z).
brotherinlaw(X, Y) :- male(X), siblinginlaw(X, Y).
sisterinlaw(X, Y) :- female(X), siblinginlaw(X, Y).
childinlaw(X, Y) :- married(X, Z), child(Z, Y).
soninlaw(X, Y) :- male(X), childinlaw(X, Y).
daughterinlaw(X, Y) :- female(X), childinlaw(X, Y).