John Corbett and Nia Vardalos in My Big Fat Greek Wedding. (AP)

It is the news that a particular kind of movie mogul has been dreading: sex no longer sells. A new study has found that films containing explicit sex or nudity do much worse at the box office, earning nearly 40 per cent less on average than more wholesome movies.

An analysis of 1,120 cinematic releases over the past four years has shown that films without sex scenes, such as Disney’s Finding Nemo or Toy Story 2, earned an average of $41.1 million, while films with sex have grossed 38 per cent less with an average of $16.7 million.

In 2003, the gap was even wider, with films without sex earning more than double those with explicit scenes. The survey also found that an increasing number of films carry a moral message, with 63 per cent of top-grossing films since 2001 portraying edifying storylines that follow uplifting and redemptive plots.

In contrast, films with an “immoral or negative content” such as Hannibal, the 2001 horror sequel to The Silence of the Lambs, or the bawdy American Pie teen-trilogy, experience far lower box office returns.

The findings, taken from an analysis of box office earnings in the US, were compiled for the Christian Film and Television Commission, a viewers’ campaign group, and published in its monthly magazine Movieguide.

Chairman of the commission Ted Baehr said: “This is a worldwide phenomenon. We found that international figures followed the same logic, that the good guys finish first. Clearly, sex does not sell as well as the mass media wants us to believe.”

Even family films that imply sex or depict it briefly are trounced by their no-sex rivals at the box office. For example, the 2002 release, My Big Fat Greek Wedding, featured passionate kissing, a naked couple in bed and several allusions to sex. Despite being marketed as a family-friendly film, it grossed £13 million in the UK, approximately 46 per cent less than Spider-Man, which contained no sex scenes.

The rise in popularity of films that are moral in tone looks set to continue after the success of Mel Gibson’s The Passion. Despite the dialogue being entirely in Latin and Aramaic, it has grossed more than $300 million since its release last month in the US. It opened in UK on March 14.

Dismissing the findings as “politically tendentious”, film critic and columnist for London’s Evening Standard Will Self said Americans were more likely to enjoy films with a religious or moral content because Christian belief remained much more entrenched in the US.