Charlie is one of the friendliest names on the planet, and Good-time Charlie is back. More and more parents (of babies of both genders) these days are opting to put the friendly, genial Charlie on birth certificates--though we'd recommend you use Charlie as a pet form of the more serious Charles.
Charlie has dozens and dozens of pop cultural references, from Charlie Chaplin to Charlie McCarthy to "Charlie's Angels" to Charlie Parker to Charlie Sheen to Charlie Rose. It derives, of course, from the classic name Charles which, in turn, comes from a German word meaning "free man." Charles became very popular in France during the Middle Ages due to the fame of Charles the Great, aka Charlemagne.
Charlie is one of the friendly, tomboyish male nickname names--another is Sam-- now used almost as frequently for girls: in 2011, it was Number 376 for girls, 236 for boys. The name Charlie, for females, has been jumping up the charts since it reappeared, after a 50-year hibernation, in 2005.
Charlie has been a favorite for starbaby girls, including the twin daughter of Rebecca Romijn and Jerry O'Connell and the daughter of Julie Chen and Les Moonves. Jeremy Sisto has a hyphenated Charlie-Ballerina.