Wizarding appears to be hereditary, but occasionally a muggle child will appear with natural magical ability, such as Harry's friend Hermione Granger .

FORBES: Harry Potter, Science Teacher

And so Hermione Granger, that charming grind, still goes to the Hogwarts library and spends hours and hours working her way through the stacks, finding out what a basilisk is or how to make a love potion.

NEWYORKER: The Information

Spoiler alert: "Harry Potter and the Deathly Hallows, Part 1" has an already well-publicized additional scene, featuring Harry Potter and Hermione Granger slow-dancing -- a nod to fans who have long wondered if the two should be more than friends.

CNN: Harry Potter and the morning after