The ‘Smurfette principle’ is the practice of including one stereotypical female character in an all-male film or TV series. It’s extremely common- April O’Neil in Teenage Mutant Ninja Turtles, Elaine in Seinfeld, Black Widow in The Avengers, Princess Leia in Star Wars, and Smurfette in The Smurfs- and there’s usually a male-dominated storyline where the lone woman is an exception who only exists in relation to the men. Source Source 2 Source 3