A porn star is a person who performs sex acts in film that is usually characterised as a pornographic film. Pornographic films tend to be made in a number of distinct pornographic sub-genres and attempt to present a sexual fantasy and the actors selected for a particular role are primarily selected on their ability to create or fit that fantasy. Pornographic films are characterised as either “softcore”, which does not contain depictions of sexual penetration or “extreme fetishism”, and “hardcore”, which can contain depictions of penetration or extreme fetishism, or both. The genres and sexual intensity of films is mainly determined by demand. Depending on the genre of the film, the on-screen appearance, age, and physical features of the main actors and their ability to create the sexual mood of the film is of critical importance. Most actors specialise in certain genres, such as lesbian sex, bondage, strap-on sex, anal sex, double penetration, semen swallowing, teenage women, interracial or MILFs. Irrespective of the genre, most actors are required to appear nude in pornographic films.