Both of my parents have rhD positive blood. I came out with rhD negative blood. How?

Question

Mum: O+
Dad: B+
Me: O-

In: 673

Answer 1

Same as skin and hair colour. I know people that both parents are blond hair blue eyed white skinned.

Daughter was born the darkest I have ever seen with short curly black hair.

The couple has a grandparent on each side that was African.

I also know twins that are totally opposite in hair colour, eye colour, skin colour and height. She is 5 ft nothing and he is over 6 ft tall.