It's often couched in the rhetoric of "virtue" and usually aimed at young women, even girls.
"Modesty is the foundation stone of chastity," former Young Women leader Elaine S. Dalton says in the May 2007 Liahona, an international LDS magazine. "Just as one does not hike trails inhabited by rattlesnakes barefoot, similarly in today's world it is essential to our very safety to be modest."
The next year, the Utah-based faith's Young Women program added "virtue" as one of the values for which Mormon girls ages 12 through 17 strive, but it was defined chiefly as sexual purity or chastity.
Today, The Church of Jesus Christ of Latter-day Saints points to a booklet called "For the Strength of Youth," which spells out guidelines for teen behavior.
"When you dress immodestly," the booklet says, "you send a message that is contrary to your identity as a son or daughter of God. You also send the message that you are using your body to get attention and approval."
This concern has reached down to girls as young as 4.
Two issues of the Friend, the church's magazine for children, carried stories about young girls who were advised to choose shirts or dresses with sleeves to be modest. One of them tells of little Hannah, who wanted to wear to the zoo a red-and-white sundress that her grandma had given her, but she noticed it didn't have any sleeves. So her mother put a T-shirt under it. "Now I am ready to go to the zoo," said the child.
Bare shoulders, even on children, are off-limits in LDS Church publications. An illustration in the December 2011 Ensign, the official magazine for adult Mormons, even added sleeves to female angels in one of painter Carl Bloch's masterpieces.
"I always laugh a bit when people say that the modesty discourse, especially toward Mormon women, is not that pervasive, because it saturates our culture," says Mormon writer and blogger Emily Jensen. "If there's one thing Mormons are good at, it's making sure other Mormons are 'measuring' up."
Modesty matters, Jensen says, but "the way we teach it matters even more."
"The current discourse on modesty undermines women's relationship to themselves, to their sexuality, and to men," LDS sex therapist Jennifer Finlayson-Fife writes in the most recent issue of Exponent II. "Far from protecting females from seeking male approval, the rhetoric on modesty unwittingly reinforces it. At the same time we are taught that pleasing men through sexual availability is not necessary, we are taught to please men and God by covering and suppressing our sexuality."
Either way, women are sexual objects.
Beware the consequences • Elder Tad R. Callister, of the church's Presidency of the Seventy, discusses what he says is "The Lord's Standard of Morality" in this month's Ensign.
Among other issues he addressed in a speech at Brigham Young University-Idaho, Callister takes up the question of modesty.
"The dress of a woman has a powerful impact upon the minds and passions of men. If it is too low or too high or too tight, it may prompt improper thoughts, even in the mind of a young man who is striving to be pure," the LDS leader says. "Men and women can look sharp and be fashionable, yet they can also be modest. Women particularly can dress modestly and in the process contribute to their own self respect and to the moral purity of men. In the end, most women get the type of man they dress for."
The Mormon general authority was echoing sentiments expressed by many other LDS leaders.
"It's very important for us to continue to talk standards, to teach them, and to encourage them, young men and young women, to be guardians of virtue, their own virtue and others because there are so many who say, 'It is not a young women's problem if a boy is doing something wrong. If she is immodest, it's not her problem if the boy does something wrong.' " Dalton, the former Young Women leader, said at a leadership training meeting last year. "Well, it is! We have to take responsibility for one another, we have to help one another."
Julie M. Smith, a Mormon writer in Austin, Texas, doesn't mind the idea of women's clothing having an effect on men being among the reasons to dress modestly, just not the main one.
Current LDS modesty discourse "doesn't focus on modesty as something that is important to the woman herself, but rather as something that is important to other people in her life," Smith writes in a blog post at timesandseasons.org. "[It] tells women that they, of themselves, do not matter … [and] contributes to the objectification of women."
She would like to see LDS leaders talk about "women's bodies as unique creations of an eternal creator who wants them to emphasize that body's ability to dance, sing, serve, ski, generate life, laugh, and cry," she writes, "and not that body's ability to conform to cultural notions of beauty or advertise the wearer's wealth or attract sexual attention from males and envy from females."
In LDS scriptures, most discussions of women's clothing are all about economics, not sexuality, says Smith, who has a master's degree in biblical studies from the Graduate Theological Union in Berkeley, Calif., "and make the case that using one's clothing to showcase wealth is a sin."
Even Jesus' famous statement about looking on a woman with lust "doesn't mention the women's clothing choices," she says in an interview, "only the man's looking."
Smith notes that the idea of modesty was not mentioned in the Friend until the mid-1990s and now has become all about wearing sleeves.
"We once had raging battles on birth control, then working moms and now modesty," Smith says. "Why do we always have to have a fight over women's bodies?"
What about the boys? • Some suggest the approach of Callister, Dalton and others is just as damaging for young men as young women.
"I have heard all my life that it is the young woman who has to assume the responsibility for controlling the limits of intimacy in courtship because a young man cannot," Jeffrey R. Holland, then-president of LDS Church-owned Brigham Young University and now an LDS apostle, said in a 1988 school devotional. "What an unacceptable response to such a serious issue.
"What kind of man is he, what priesthood or power or strength or self-control does this man have that lets him develop in society, grow to the age of mature accountability, perhaps even pursue a university education and prepare to affect the future of colleagues and kingdoms and the course of the world, but yet does not have the mental capacity or the moral will to say, 'I will not do that thing'?"
A "sorry drugstore psychology" would suggest that such a man is helpless before such attractions, his "glands have complete control over his life his mind, his will, his entire future," Holland said. "To say that a young woman in such a relationship has to bear her responsibility and that of the young man's, too, is the least fair assertion I can imagine."
Jana Riess, a popular LDS blogger, comments on this double standard in a recent satirical post for Religion News Service in which she urged young Mormon men to be mindful of what they wear to keep young women from straying to "lustful thoughts."
"Away with shoulder-baring tank tops during your pickup basketball games in the church gym," she writes. "Away with low-slung jeans that drive girls crazy wondering by what defiance of physics your pants don't drop to your ankles."
Then, in a twist on Callister's speech, Riess reminds Mormon men that they will marry "the type of woman you dress for."
Brad Kramer, a Utah-based anthropologist who studies the effects of language on Mormon communities, argues that there is a distinction between thoughts and actions.
Mormon males "feel a degree of guilt when any sexual desire is triggered by someone other than their wife, and they partially blame and resent the girl/woman in question if modesty rhetoric has given them a pretext for judging their dress as inappropriate," Kramer says. "You see this play out especially strongly in the mission field, where young men feel the strongest pressure to completely suppress desire. You encounter an awful lot of resentment and sometimes vivid hostility in male missionaries toward local girls and women who trigger sexual desire or attraction."
Even a naked woman would be responsible only for "triggering desire or reflective arousal, which is not by itself sinful," Kramer says. "If I indulge that reflexive reaction to what I see or act on it, that is me and me alone."
In a wider American culture that "trivializes sexuality," Mormon men and women fear that "sexuality may undermine our spiritual progression," Finlayson-Fife writes, "keep us from God, and cost us our social standing."
The church's modesty mantra creates deep anxiety about human sexuality, she says, and "does women (and men) a deep disservice."
Such anxiety "robs women of self-knowledge, as well as ownership of and confidence in their sexuality."
Mormon doctrine posits that women are "sexual beings … [with] beautiful, curvaceous bodies," the therapist writes. True modesty, then, includes honoring womanly sexuality "neither flaunting it nor masking it."