Time Magazine’s sensational cover may have made a few subscribers squirm — and it’s ignited a fervent discussion about attachment parenting and breast-feeding. Beyond that, photographer Martin Schoeller’s image of 26-year-old mom Jamie Lynne Grumet breast-feeding her three-year-old son has inspired conversations about what makes a good cover, and what pushes the boundaries of taste.

Schoeller said in Time’s “Behind the Cover” article that he looked to religious imagery of the Madonna and Child for inspiration in creating this provocative contemporary image.

This image provided by Time magazine shows the cover of the May 21, 2012 issue with a photograph of Jamie Lynne Grumet, 26, breast-feeding her 3-year-old son for a story on "attachment parenting." (Associated Press)

Pushing the boundaries is what makes a cover great, according to the Post’s visuals editor, David Griffin. He’s guided National Geographic and U.S. News & World Report in their cover designs previously, and was intrigued by Time’s arresting image.

“[A good cover] should always be what contemporary social norms can barely handle,” Griffin said. “My feeling is, you want to produce enough covers each year that people will remember you as a publication. When they look to renew, you risk the chance that they will forget about you.”

Designers make their cover decisions based not just on the story, but also on marketing. A provocative cover may spark newsstand sales, but more of a magazine’s earnings come from subscribers, typically — and since those subscribers have already bought the cover and may not like what they’ve paid for, it also risks offending them.

“That is the line that you ride,” says Griffin. “If it’s too safe, you disappear into the static of all other publications. If it’s too risky, you risk offending your core readership ... You have to balance the short-term gain of sales against long term damage.”

Another risk: Once a sensational cover is out there, the magazine can lose control of its own image, via the viral parodies (Caution: Some of the parodies may be offensive.) that pop up on blogs. Readers have photoshopped other faces onto Grumet’s and her son’s for laughs. Even if they’re mocking the cover, viral interest in the image will only benefit Time — but Griffin thinks that’s not the only reason it was selected.

“No one picks [a cover] merely for it to go viral. You choose a photo to draw attention to an issue,” he said. “A photo, to be powerful, has to focus on one element of a story. It’s rare to find one photo that can sum up an entire story. Photography reduces concepts to the visceral, the emotional.”

This cover gets its power from the confrontational way that both Grumet and her son, Aram, are looking directly at the viewer, as if daring someone to challenge her unconventional parenting methods.

“When you think of breast-feeding, you think of mothers holding their children, which was impossible with some of these older kids,” cover photographer Schoeller told Time. “I liked the idea of having the kids standing up to underline the point that this was an uncommon situation.”

But though the cover may make some readers squeamish, its imagery has a precedent deep in art history, where the image of a woman breast-feeding — and even breast-feeding someone older than a child — is less controversial.

Schoeller’s decision to evoke the Madonna and Child brings to mind other paintings and sculptures of unusual situations in breast-feeding that go further back in history. In Roman mythology, the ancient founders of the city, Romulus and Remus, are often depicted suckling the teat of a she-wolf. According to another story from ancient Rome — this one by the historian Valerius Maximus — a daughter, Pero, saves her incarcerated father, Cimon, from starvation by secretly breast-feeding him. The image, often called “Roman Charity,” has been interpreted by painters including Caravaggio and Peter Paul Rubens, and the man breast-feeding in those paintings is much, much older than a three-year-old.

Peter Paul Rubens’s “Roman Charity”.