I knew at least one '70s-spawned Jennifer named for Ali MacGraw’s character in Love Story, which was the highest grossing film of 1970. I don’t know if that’s the main factor in that particular spike, but I don’t imagine it hurt.
One definite movie-related spike is “Madison”. In 1984’s Splash, Tom Hanks rightly said “Madison’s not a name”. But because of that movie – and its main character with a name cribbed from a street sign – it became one of the most popular girls’ names for several years.
