Some insight into this topic- I'm married and my husband is biracial. His Father is of black Caribbean descent and Mother of white European descent. Last year we welcomed our son in August a healthy beautiful baby boy. Within weeks of my son's birth rumours started circulating about the resemblance of my son and his father. It was loosely joked that he wasn't my husband's son and this was mainly to do with how "white" my son appeared. I shut down such rumours on my side of the family and made it clear that I was not engaging in such speculation or entertaining people's ignorance.
My son is very light skinned he is actually quite pale. He has light hair which looks blonde when the sun hits it and brown eyes. He looks like me a lot especially when I was a baby though he does have his father's head shape and certain characteristic traits that I and his father see. Though when you look at him his resemblance is very much from my side of the family.
My SIL keeps making comments about how white he is, it's all she ever mentions when she sees him. She'll say things like..."little white boy." Or "I just don't see you (my husband.) in him."
It's actually not uncommon for babies to have features or skin tones that may not directly mirror those of their parents.
My husband's other sister has three children all from the same father and the father my brother in law actually has the same heritage as me, I am half Italian half Irish, he is half Italian half English. My husband's nephew their son is white with ginger hair and freckles and their twin daughters are darker more mixed race looking. You would think my sister in law who keeps mentioning my son's skin tone would think well her other nephew has white skin with freckles so why is it such a problem that my son has white skin? I think it's because she knows for certain that her other nephew is her nephew because he was born from her sister where my son was born from me so there's doubts.
How do I challenge this as she hasn't out right said she doesn't believe my son isn't my husbands but you know from the comments and looks that she believes my son is not my husband's.