father(abraham,isaac).			
father(haran,lot).			
father(haran,milcah).			
father(haran,yiscah).

male(isaac).
male(lot).

female(milcah).
female(yiscah).

son(X,Y) :- father(Y,X), male(X).
daughter(X,Y) :- father(Y,X), female(X).

%Program 1.2: Biblical family relationships