Baby doesn't resemble parents

Does anyone have a child that does not look like either parent? I have a 6 month old baby who is mixed and I have been hearing the "She doesn't look like you or her dad" and it is starting to annoy me "are you sure she is his?" "Daughters are supposed to look like their dads and sons like their mother" okay so which scientist wrote this? Last time I checked it takes two people to create a child with very complex genes a child isn't always going to resemble his or her parents.