Crazy mother in law

Does anyone else have a crazy mother in law?

She swears our 2 year old son isn’t my husbands because our son has green eyes and me and my husband both have brown. Even though I’ve tried explaining biology to her by telling her that all my sisters have green or blue eyes and my mother in law herself has green eyes so we have passed on the trait but she refuses to believe me. 🤦🏼‍♀️🤦🏼‍♀️🤦🏼‍♀️