To paraphrase Tolstoy, “Every happy family snapshot is the same, but unhappy family photos are all different.” Such might be a tentative conclusion from “Family Pictures,” which opens February 9 at the Guggenheim Museum. The exhibit, which includes work by Gregory Crewdson, Loretta Lux, and Robert Mapplethorpe, among others, aims to explore the “representation of families and children in contemporary photography and video.” It also raises the question: Is it acceptable to use one’s own family as photographic fodder for art?

The Victorian British photographer Julia Margaret Cameron (1815–79) was a typical early instance of using family members as models. Cameron repeatedly posed her infant grandson, Archie Cameron, as the Baby Jesus in photos with titles such as “Light and Love” and “Hosanna” (both from 1865). Cameron explained to a friend that in such spiritually exalted images, she tried to capture the “real child & to combine power with softness.”

Although forced into Cameron’s personal mythology of the sacral family circle, her young models were by no means demeaned. Times have changed. The Virginia-born photographer Sally Mann (b. 1951), whose images are included in the Guggenheim show, attracted criticism for her 1992 book, “Immediate Family,” which included nude photographs of her three young children looking rather grimy, anguished, and forlorn.

Ms. Mann’s is not an isolated case. Atlanta-born Tierney Gearon (b. 1963) shows photos of her small children nude on the beach, urinating in the snow, and seated on the toilet. Her series “The Mother Project,” which features uncompromising views of her schizophrenic mother, was on display last fall at Yossi Milo Gallery in Chelsea and provided the subject matter for “Tierney Gearon: The Mother Project,” a 70-minute documentary that made its premiere at last year’s Tribeca Film Festival.

These and other photographers evoke praise from titillated critics as well as moral outrage from parts of the public. Others are simply repelled. After all, photographs of a subject — no matter his or her age — cannot be published without legal consent, if the person has a “reasonable expectation of privacy” at the time the photograph was snapped. The entire span of childhood may be termed a time of “reasonable expectation of privacy,” a belief that even Hollywood stars, whose notoriety depends on paparazzi, can cherish. Yet photographers who display nude or other potentially disturbing images of their own children can show a total disregard of the reality of the young persons depicted. Every photograph is an interpretation, and such images present a double violation: Not only may a child’s privacy be violated, but the violation is committed with the permission of the parent — in this case the photographer.

These rules do not only apply to nudity in fine art, but to lowbrow imagery as well. The Australianborn photographer Anne Geddes (b. 1956) has sold millions of calendars and books of photos of babies dressed as bunnies, butterflies, and pearls, and sometimes tucked inside fabricated cabbage leaves and flower petals. They are as unnaturally perverse as any imagery at the Guggenheim show, yet socially approved because they are deemed “cute” by many.

Children are not the only vulnerable family targets for high-art shutterbugs. The British photographer Richard Billingham (b. 1970) has won acclaim for his book “Ray’s a Laugh” (1996), depicting his slum-dwelling parents in Birmingham, England. Mr. Billingham describes his groggy father as a “chronic alcoholic,” while his obese, tattooed mother is hardly less dazed. These helpless, hapless folk are shown sprawled around their hovel; Mr. Billingham has justified the invasion of privacy by explaining: “I was just trying to make order out of chaos.”

Such is the goal of every artist, and photographers, especially impoverished ones, naturally tend to use family models who are free and nearby. Yet great photographers have employed family models without compromising their personal privacy and integrity. A case in point is the Kentucky photographer Ralph Eugene Meatyard (1925–72), whose poetic, spooky imagery was on view at a 2005 exhibit at the International Center of Photography. Meatyard posed his children in abandoned Kentucky plantation houses, and the lonely feeling of abandonment that emanates from his images seems to draw as much from romantic childhood imaginings as from adult photographic ambitions. For every Meatyard who creates a cohesive emotional reality for his subjects, however, there are many photographers who betray family subject matter.

Photographers are not the only creative personalities who are guilty of such betrayals. Poets can be notorious for their disregard of family privacy. In her poem “Bathing the New Born,” the New York poet Sharon Olds describes her baby son’s scrotum in detail. In another poem, “Rite of Passage,” she quotes him — with high-handed disapproval — at his 6th birthday party. Robert Lowell (1917–77) in his collection, “The Dolphin,” quoted verbatim from the letters of his ex-wife and young daughter without permission.

To such writers or the photographers who emulate their intrusions, the Golden Rule might be of service. Readers or viewers can conclude: I myself would not like to be photographed urinating and displayed in public to be ogled at, therefore why should I approve of someone else — especially a minor — being placed in this situation? Whatever the content of the forthcoming Guggenheim show proves to be, it is time that discretion and respect for the personal authenticity of the subject — as opposed to mere exhibitionism or prudery — governed more photographers’ aesthetic. Otherwise, based on cultural evidence, future generations may think of the family circle of our era as belonging to a level of Dante’s Hell.