mutter(ann, henry).
mutter(ann, mary).
mutter(jane, mark).
mutter(jane, francis).
mutter(anette, jonathan).
mutter(mary, bill).
mutter(janice, louise).
mutter(lucy, janet).
mutter(louise, caroline).
mutter(louise, martin).
vater(henry, jonathan).
vater(john, mary).
vater(francis, louise).
vater(john, mark).
vater(gavin, lucy).
vater(john, francis).
vater(martin,david).
vater(martin,janet).