Trying to learn to ignore this girl's idiosyncrasies, Hermione nodded. "Yes, well, that's more or less how it works at home, too. But a witch and a wizard are almost always going to have a child with magic, and two Muggles - that's a person who can't do magic- will almost always have a Muggle child. Occasionally you'll get a Muggle-born witch or wizard, like me, and rarely you'll get a Squib, someone born to a wizarding family but who can't use magic. But essentially, anyone who can use magic has to go to school for it, so they don't just accidentally... blow up a restaurant or something."