This actually reminds me of a great story I heard once. So, this young, good looking couple (man and woman) enter a bar and the man happily announces they are going to get married soon. Everyone cheers the couple and the man buys a round a drinks for everyone. The man then starts bragging to the bartender about how they are going to have good looking children, because they both are so good looking. The woman appears very embarrassed from all this attention, and when the man leaves to use the restroom the bartender approaches the woman and asks if she's okay. The woman admits to the bartender that the man has no idea that before they met, she had extensive plastic surgery to look this way. Her teeth, nose, chin, body, almost everything is fake. Therefore, the children are probably not going to look anything like he thinks they will, and she doesn't have the heart to warn him.
So, you could think of it like that; maybe one of the parents doesn't actually look like they appear.
