male(george).
male(phillip).
male(spencer).
male(charles).
male(mark).
male(andrew).
male(edward).
male(william).
male(harry).
male(peter).
male(mike).
male(james).
male(george2).

spouse(george, mum).
spouse(elizabeth, philip).
spouse(spencer, kydd).
spouse(diana, charles).
spouse(anne, mark).
spouse(andrew, sarah).
spouse(edward, sophie).
spouse(william, catherine).
spouse(peter, autumn).
spouse(zara, mike).

child(elizabeth, mum).
child(margaret, mum).
child(charles, elizabeth).
child(anne, elizabeth).
child(andrew, elizabeth).
child(edward, elizabeth).
child(diana, kydd).
child(william, diana).
child(harry, diana).
child(peter, anne).
child(zara, anne).
child(beatrice, sarah).
child(eugenie, sarah).
child(louise, sophie).
child(james, sophie).
child(george2, catherine).
child(charlotte, catherine).
child(savannah, autumn).
child(isla, autumn).
child(mia, zara).

is_spouse(X, Y) :-
  spouse(X,Y);
  spouse(Y,X).

is_child(X, Y) :-
  child(X, Y);
  (is_spouse(Z, Y),
    child(X, Z)).

grandchild(X, Y) :-
  is_child(Z, Y),
  is_child(X, Z).

greatgrandparent(X, Y) :-
  (is_child(Z, X),
  is_child(A, Z),
  is_child(Y, A));
  (is_spouse(X,B),
  is_child(Z, B),
  is_child(A, Z),
  is_child(Y, A)).

ancestor(X, Y) :-
  is_child(Y, X);
  (is_child(Z, X),
  ancestor(Z, Y)).

brother(X, Y) :-
  child(X, A),
  child(Y, A),
  male(X),
  \==(X, Y).

sister(X, Y) :-
  child(X, A),
  child(Y, A),
  \+ male(X),
  \==(X, Y).

daughter(X, Y) :-
  is_child(X, Y),
  \+ male(X).

son(X, Y) :-
  is_child(X, Y),
  male(X).

first_cousin(X, Y) :-
  (uncle(A, X),
    is_child(Y, A)).

brother_in_law(X, Y) :-
  (spouse(B, X),
  child(B, A),
  child(Z, A),
  spouse(Y, Z),
  \+ is_spouse(Y, X),
  male(X));
  (child(X, A),
  child(Z, A),
  spouse(Y, Z),
  \+ is_spouse(Y, X),
  male(X)).

sister_in_law(X, Y) :-
  (spouse(B, X),
  child(B, A),
  child(Z, A),
  spouse(Y, Z),
  \+ is_spouse(Y, X),
  \+ male(X));
  (child(X, A),
  child(Z, A),
  spouse(Y, Z),
  \+ is_spouse(Y, X),
  \+ male(X)).

aunt(X, Y) :-
  is_child(Y, Z),
  sister(X, Z).

uncle(X, Y) :-
  is_child(Y, Z),
  brother(X, Z).

cousin(X, Y) :-
  first_cousin(X, Y).