The question has been pondered by mystics through the ages, but in the sanctuary of cinema the voice of a sonorous, authoritative, fear-inspiring yet sometimes relatable presence is, invariably, that of a man. Consider the trailer and the omniscient, disembodied voice that introduces moviegoers to a fictional world.

“Most movie trailers are loud and strong, and film studios want that male impact, vocally and thematically,” said Jeff Danis, an agent who represents voice-over artists. “Even if it’s a romantic comedy or nonaction movie, they still want that certain power and drama that men’s voices tend to convey on a grander scale.”

Even now movie trailers and promos largely hew to a template created 40 years ago byDon LaFontaine, Hollywood’s most prolific voice-over artist. Possessor of a resonant baritone that could cut through tight sequences of music and sound bites — and the coiner of familiar (and parodied) phrases like “In a world ...” and “One man, one destiny” — LaFontaine, who died in 2008, voiced more than 5,000 trailers, 350,000 commercials and thousands of television promos.

In the past few years, as audiences have grown more sophisticated, the independent production companies that make trailers for Hollywood studios have begun moving away from voice-overs, favoring graphic devices like title cards to serve as narration. “As much as possible people are trying to let the movie speak for itself, without being as heavy handed as the ‘voice of God’ narrator feels,” said John Long of Buddha Jones Trailers, which was responsible for campaigns for “Kung Fu Panda 2” and “Inglourious Basterds,” among others.

Still, plenty of voice-over jobs remain, especially in television, though women are seldom cast. “There are some very talented, very gifted women in this business that can satisfy any request for a narrator, but the opportunities aren’t given to them,” said Mike Soliday, a talent agent who represents prominent male voice artists like Scott Rummell and Tony Rodgers.

As Mr. Danis put it, “Trailers are really the last frontier for women.”

Mr. Long noted that his company had worked on dozens of campaigns a year, “and as much as everyone talks about wanting to be innovative and do unexpected things, the idea of a female voice doesn’t come up that often,” he said. “It’s really not part of the formula. Maybe that’s our own shortsightedness.”

Asked to name a theatrical campaign that featured a female voice, trailer makers interviewed for this article could easily recall just one: “Gone in 60 Seconds,” the 2000 action thriller that starred Nicolas Cage and Angelina Jolie. “It was filled with really sexy and fast and fantastic-looking cars, and shot with a ton of energy,” recalled Skip Chaisson of Skip Films, who produced the trailer. “What else did it need? I thought it would be cool if we had a really sexy female voice. In a way we were doing a car commercial, so why not go as far with it as we can?”

Melissa Disney, who did the voice-over for “Gone in 60 Seconds” and works frequently on television promos, commercials and animated series, argued that “men are very attracted to women’s voices, especially when they are sexy and sultry.” She continued: “Women have such a large range. We have so much more to pull from than your typical male action voice.”

One challenge women face is the perception in the industry that it’s difficult for their voices to be heard over a trailer’s cacophony, an attitude some voice-over artists dispute. “To say that a woman’s voice won’t cut through a trailer just isn’t true,” said Joan Baker, the author of “Secrets of Voice-Over Success” and a friend of LaFontaine’s. “What women’s voices have is emotionality and color and a certain kind of rhythm. Don would even say, ‘My voice isn’t right for everything.’ He felt it was ridiculous that women were not used in movie trailers. But no one wants to change what isn’t broken.”

Do moviegoers want to hear female voices? Research indicates that our brains are wired to prefer theirs to male ones; that’s the reason robotic voices, like those in GPS devices, tend to be female. (This probably has an evolutionary explanation: fetuses in the womb, identifying with their caretaker, can distinguish their mother’s voice from others, a study published in the journal Psychological Science found.) When it comes to credibility, however, research into the perceived believability of a voice — an important quality for the omniscient narrator of a trailer, as well as the spokesman or -woman for any product, which is the function a trailer serves — tells a different story.

“On average both males and females trust male voices more,” said Clifford Nass, a professor of communications at Stanford, noting some gender disparity exists in that women don’t distrust female voices as much as men distrust them. In one study conducted at Stanford two versions of the same video of a woman were presented to subjects: one had the low frequencies of the woman’s voice increased and the high frequencies reduced, the other vice versa. Consistently subjects perceived the deep voice to be smarter, more authoritative and more trustworthy.

Science aside, the conventional wisdom in the movie industry has it that audiences respond more favorably to trailers with male voice-overs. “People don’t buy that product from women, and I don’t know why,” said Seth Gaven of AV Squad, which produced the trailers and television campaigns for “The King’s Speech” and “Captain America.” “Female voice-overs don’t have the same credibility. Sometimes I’ll even consider a few guys with similar voices, and one might be a little more resonant and commanding, even in a subtle way. He usually gets the job.”

In television many cable channels regularly aim programming at women, and there has been more latitude in the use of female voices. “We’re all trying to make shows that cut through the clutter and stick out,” said Tim Nolan, senior vice president for marketing at Lifetime Networks. “But for me it’s less about being authoritative and more about being relatable. It’s a big turnoff for TV consumers if they think they’re being sold. Whether the show’s about fashion or drama or reality, it’s about which voice is telling those stories better.”

In testing “One Born Every Minute,” a Lifetime series set in an Ohio maternity ward, the channel found that audiences responded most favorably to a voice-over by Jamie Lee Curtis, even before they recognized her, Mr. Nolan recalled, adding: “One women said that the voice understood who she was.”