Look for a mother of a child

Hello, 


I have these facts:


male(roelof). 

male(mans).

male(jan).


female(chantal). 

female(tamara). 

female(marie). 


parent(roelof,tamara).

parent(mans, roelof). 

parent(jan, chantal). 

parent(marie, roelof). 

parent(chantal, tamara). 


mother(child):- 

parent(X, child),

female(X).


But when I do mother(tamara). I see no where I expected to see chantal.


Did I do something wrong or does swi-prolog do something wrong ?


Roelof