Veronica Cartwright (Rosalie) said in an interview that she and the other children were told not to hang around with Shirley MacLaine on set because she "cursed a lot". They all did, however, because they thought she was "cool" and "very generous". She also became Cartwright's mentor throughout the making of the film.
William Wyler cut several scenes hinting at Martha's homosexuality for fear of not receiving the seal of approval from the Motion Picture Production Code. At the time, any story about homosexuality was forbidden by the production code.
The original stage-play was partly inspired by an actual case in Edinburgh, Scotland in 1810. A pupil named Jane Cumming accused her schoolmistresses, Jane Pirie and Marianne Woods, of having an affair. Dame Cumming Gordon, the accuser's influential grandmother, advised her friends to remove their daughters from the boarding school. Within days the school was deserted and the two women had lost their livelihood. Pirie and Woods sued and eventually won, both in court and on appeal, but given the damage done to their lives, their victory was considered hollow.
The start of the movie implies that Mary gets the idea to "accuse" Karen and Martha of lesbianism from a forbidden book that gets passed around secretly among the school's students. Although this book is not identified by title in the movie, Lillian Hellman's play specifies that the book is Mademoiselle de Maupin, by Théophile Gautier, a French novel published in 1835. The novel concerns a woman who disguises herself as a man and has both a woman and a man fall in love with her, so it did contain at least the concept of lesbianism and, therefore, answers the question of how Mary could have conceived of the charge she levels against Martha and Karen without ever actually seeing them engage in any romantic or sexual activity.
Shirley MacLaine, in the documentary The Celluloid Closet (1995), said that nobody on the set of The Children's Hour (1961) discussed the ramifications of the issues regarding homosexuality that are implied, but never spoken about outright, in the film. She said, "none of us were really aware. We might have been forerunners, but we weren't really, because we didn't do the picture right. We were in the mindset of not understanding what we were basically doing. These days, there would be a tremendous outcry, as well there should be. Why would Martha break down and say, 'Oh my god, what's wrong with me, I'm so polluted, I've ruined you.' She would fight! She would fight for her budding preference. And when you look at it, to have Martha play that scene - and no one questioned it - what that meant, or what the alternatives could have been underneath the dialog, it's mind boggling. The profundity of this subject was not in the lexicon of our rehearsal period. Audrey and I never talked about this. Isn't that amazing. Truly amazing."