father_of(jim,me).
sister_of(cindy, me).
sister_of(meg,me).
mother_of(joan,me).

male(X):-
      father_of(X,Y).


parent_of(X,Y):-
      mother_of(X,Y);
      father_of(X,Y).

male(me).

sibling_of(X,Y):-
      sister_of(X,Y);
      sister_of(Y,X).
brother_of(X,Y):-
      male(X),
      sibling_of(Y,X).