From the silver screen to the birth register

Harry Potter came out, and suddenly every second baby boy was named Harry. Twilight came out, and every second baby girl was named Bella. Frozen came out, and suddenly we were drowning in Elsas. Movies don't just entertain us — they rename us.

The Harry Potter effect is the biggest one. Before 1997, Harry was a classic but slightly dusty name — think Harry Potter's dad, not Harry Potter. Then J.K. Rowling wrote a book, and suddenly Harry was cool again. It went from "grandpa name" to "hero name" overnight.

Twilight did the same for Bella. Before 2005, Bella was a cute retro name. After Twilight, it was everywhere. Same with Elsa after Frozen. Same with Olivia after... well, Olivia was already popular, but Shakespeare gave it a boost.

The funny thing is, the effect usually lasts about 5-10 years, then fades. By the time the movie's kids are in high school, the name has moved on. So if you named your daughter Elsa in 2013, she's now a teenager who's probably sick of hearing "let it go". Sorry about that.