Continuity mistake: Early in the film, Henry Fonda and another juror are in the men's room. When the other juror exits, the door is a swinging door. From the jury room the door is a regular door with a door knob. You can hear the door close when Henry Fonda exits and closes the door.
12 Angry Men (1957)
1 continuity mistake - chronological order
Directed by: Sidney Lumet
Starring: Henry Fonda, Martin Balsam, Lee J. Cobb, John Fiedler, Jack Klugman, E.G. Marshall
Visible crew/equipment: When Juror 8 is approaching Juror 4 following the revelation of the witness across the street's eyesight being put under question, as the camera moves in, its shadow is seen moving across the back of Juror 3. (01:28:55)
Juror #5: Boy oh boy, it's really hot, huh? Pardon me, but don't you ever sweat?
Juror #4: No, I don't.
Trivia: This was the only film ever produced by Henry Fonda. The work of both acting and producing was so demanding that he said afterwards that he would never produce another film.
Answer: Depends where, and the type of case. At the time the film was made, women were still barred from juries in three states (South Carolina, Mississippi, and Alabama); it wasn't until 1994 that the Supreme Court ruled that lawyers could not strike women from juries solely on the basis of gender. SCOTUS had ruled in 1942 that all-male juries were constitutionally acceptable. New York State (where the story is set) had granted women the right to serve on juries in 1927, so an all-male jury may not have been the norm across the board, but the nature of the crime (murder) would have, at the time, allowed lawyers to exclude women at the jury selection stage by citing the unsavoury aspects of the crime and arguing that the details of the case were not "suitable" for women to hear (being such delicate creatures, you understand /s).