My Mom tells me that she has observed people "change from looking like one of their parents into looking like the other parent in an instant just because the angle of the light in the room changed".
When your a child and a teen your facial feature grow at different rates, but even after that - as an adult you gain or loose wieght or change your hairstyle, or men change their facial hair style (gain or loose mustaches and goatees) all which effects which parent you look like. Doesnt really mean anything.