On March, 31, 1930, the Motion Pictures Production Code was instituted, imposing strict guidelines on the treatment of sex, crime, religion and violence in film for the next 38 years. From the article:
"Production Code 1934
The Motion Picture Production Code of 1930
If motion pictures present stories that will affect lives for the better, they can become the most powerful force for the improvement of mankind.
A Code to Govern the Making of Talking, Synchronized and Silent Motion Pictures. Formulated and formally adopted by The Association of Motion Picture Producers, Inc. and The Motion Picture Producers and Distributors of America, Inc. in March 1930.
Motion picture producers recognize the high trust and confidence which have been placed in them by the people of the world and which have made motion pictures a universal form of entertainment. They recognize their responsibility to the public because of this trust and because entertainment and art are important influences in the life of a nation.
Hence, though regarding motion pictures primarily as entertainment without any explicit purpose of teaching or propaganda, they know that the motion picture within its own field of entertainment may be directly responsible for spiritual or moral progress, for higher types of social life, and for much correct thinking.
During the rapid transition from silent to talking pictures they have realized the necessity and the opportunity of subscribing to a Code to govern the production of talking pictures and of re-acknowledging this responsibility.
On their part, they ask from the public and from public leaders a sympathetic understanding of their purposes and problems and a spirit of cooperation that will allow them the freedom and opportunity necessary to bring the motion picture to a still higher level of wholesome entertainment for all the people.
General Principles
1. No picture shall be produced that will lower the moral standards of those who see it. Hence the sympathy of the audience should never be thrown to the side of crime, wrongdoing, evil or sin.
2. Correct standards of life, subject only to the requirements of drama and entertainment, shall be presented.
3. Law, natural or human, shall not be ridiculed, nor shall sympathy be created for its violation.
Particular Applications
I. Crimes Against the Law: These shall never be presented in such a way as to throw sympathy with the crime as against law and justice or to inspire others with a desire for imitation.
Murder
The technique of murder must be presented in a way that will not inspire imitation.
Brutal killings are not to be presented in detail.
Revenge in modern times shall not be justified.
Methods of Crime should not be explicitly presented.
Theft, robbery, safe-cracking, and dynamiting of trains, mines, buildings, etc., should not be detailed in method.
Arson must subject to the same safeguards.
The use of firearms should be restricted to the essentials.
Methods of smuggling should not be presented.
Illegal drug traffic must never be presented.
The use of liquor in American life, when not required by the plot or for proper characterization, will not be shown.
II. Sex: The sanctity of the institution of marriage and the home shall be upheld. Pictures shall not infer that low forms of sex relationship are the accepted or common thing.
Adultery, sometimes necessary plot material, must not be explicitly treated, or justified, or presented attractively.
Scenes of Passion
They should not be introduced when not essential to the plot.
Excessive and lustful kissing, lustful embraces, suggestive postures and gestures, are not to be shown.
In general passion should so be treated that these scenes do not stimulate the lower and baser element.
Seduction or Rape
They should never be more than suggested, and only when essential for the plot, and even then never shown by explicit method.
They are never the proper subject for comedy.
Sex perversion or any inference to it is forbidden.
White slavery shall not be treated.
Miscegenation (sex relationships between the white and black races) is forbidden.
Sex hygiene and venereal diseases are not subjects for motion pictures.
Scenes of actual child birth, in fact or in silhouette, are never to be presented.
Children’s sex organs are never to be exposed.
III. Vulgarity: The treatment of low, disgusting, unpleasant, though not necessarily evil, subjects should always be subject to the dictates of good taste and a regard for the sensibilities of the audience.
IV. Obscenity: Obscenity in word, gesture, reference, song, joke, or by suggestion (even when likely to be understood only by part of the audience) is forbidden.
V. Profanity: Pointed profanity (this includes the words, God, Lord, Jesus, Christ – unless used reverently – Hell, S.O.B., damn, Gawd), or every other profane or vulgar expression however used, is forbidden.
VI. Costume
Complete nudity is never permitted. This includes nudity in fact or in silhouette, or any lecherous or licentious notice thereof by other characters in the picture.
Undressing scenes should be avoided, and never used save where essential to the plot. Indecent or undue exposure is forbidden.
Dancing or costumes intended to permit undue exposure or indecent movements in the dance are forbidden.
VII. Dances
Dances suggesting or representing sexual actions or indecent passions are forbidden.
Dances which emphasize indecent movements are to be regarded as obscene.
VIII. Religion
No film or episode may throw ridicule on any religious faith.
Ministers of religion in their character as ministers of religion should not be used as comic characters or as villains.
Ceremonies of any definite religion should be carefully and respectfully handled.
IX. Locations: The treatment of bedrooms must be governed by good taste and delicacy.
X. National Feelings
The use of the Flag shall be consistently respectful.
The history, institutions, prominent people and citizenry of other nations shall be represented fairly.
XI. Titles: Salacious, indecent, or obscene titles shall not be used.
XII. Repellent Subjects
The following subjects must be treated within the careful limits of good taste:
Actual hangings or electrocutions as legal punishments for crime.
Third degree methods.
Brutality and possible gruesomeness.
Branding of people or animals.
Apparent cruelty to children or animals.
The sale of women, or a woman selling her virtue.
Surgical operations
Source: Leff, L. J., & Simmons, J. L. (1990). The dame in the kimono: Hollywood, censorship, and the production code from the 1920s to the 1960s. New York: Grove Weidenfeld."