How odd! If your DD was 14 then I would say she was rude but she's 4!! It sounds to me like she's just curious and wasn't rude, just inquisitive. My DH's father is Indian and I remember when he first met DD1 who was about 4 too and she asked him how he could be my hubby's dad when his skin was brown! He laughed and tried his best to explain, he wasn't offended, she was just asking, how else do they learn?