The audacity!!!

My sister in-laws were meeting my son for the first time and the first thing that they did was check his body for birthmark! They found the birthmark and said “yeah he is definitely our brother’s child because every legitimate child in our family have that birthmark. We all do”. Now what kinda rubbish is that?! So if he didn’t have the birthmark, that would make him less of his father’s child?? I was so pissed off that I told them to leave. Now my husband is saying that I was rude. Rude how? Why check for birthmark first before hugging your nephew! Did they have doubts that the child would be for my husband? What if we have another child and the child does not have the birthmark?! I was upset about their reaction and statement