Is Maria Robotnik and Doctor Eggman cousin?

Yes, Maria Robotnik and Doctor Eggman (also known as Dr. Ivo Robotnik) are cousins. Maria is the granddaughter of Professor Gerald Robotnik, while Eggman is his direct descendant, making them part of the same family lineage. Their connection is explored in the Sonic the Hedgehog series, particularly in the backstory involving the characters and their relationships.