X-rated films are movies that contain explicit sexual content and are intended for adult audiences only. These films are typically marked with an "X" rating, indicating that they are not suitable for viewers under a certain age, often 17 or 18. The content may include graphic depictions of sexual acts, nudity, and adult themes. Historically, the X rating was used by the Motion Picture Association of America (MPAA) until it was replaced by the NC-17 rating in 1990. However, many independent films still use the X rating to signify adult content. X-rated films can be controversial and are often subject to censorship and legal restrictions in various countries.