Originally more common as a name for boys in America, it became more popular for girls in the 1960s. It began rapidly increasing after 1973, possibly due to a character (played by Natalie Wood) in the television movie The Affair. It reached an apex in the United States ranked 17th in 1990, though it has quickly fallen away since then.
In the English-speaking world this name is more commonly given to girls. This is due to the American actress Alexis Smith (1921-1993), who began appearing in movies in the early 1940s. It got a boost in popularity in the 1980s from a character on the soap opera Dynasty.