"I was SHOCKED to see a giant breast on the cover of your magazine," one person wrote. "I immediately turned the magazine face down," wrote another. "Gross," said a third.

These readers weren't complaining about a sexually explicit cover but rather one of a baby nursing, on a wholesome parenting magazine — yet another sign that Americans are squeamish over the sight of a nursing breast, even as breast-feeding itself gains greater support from the government and medical community.

Babytalk is a free magazine whose readership is overwhelmingly mothers of babies. Yet in a poll of more than 4,000 readers, a quarter of responses to the cover were negative, calling the photo — a baby and part of a woman's breast, in profile — inappropriate.

One mother who didn't like the cover explains she was concerned about her 13-year-old son seeing it.

"I shredded it," said Gayle Ash, of Belton, Texas, in a telephone interview. "A breast is a breast — it's a sexual thing. He didn't need to see that."

It's the same reason that Ash, 41, who nursed all three of her children, is cautious about breast-feeding in public — a subject of enormous debate among women, which has even spawned a new term: "lactivists," meaning those who advocate for a woman's right to nurse wherever she needs to.

"I'm totally supportive of it — I just don't like the flashing," she said. "I don't want my son or husband to accidentally see a breast they didn't want to see."

Another mother, Kelly Wheatley, wrote Babytalk to applaud the cover, precisely because, she said, it helps teach people that breasts are more than sex objects. And yet Wheatley, 40, who's still nursing her 3-year-old daughter, rarely breast-feeds in public, partly because it's more comfortable in the car, and partly because her husband is uncomfortable with other men seeing her breast.

"Men are very visual," said Wheatley, 40, of Amarillo, Texas. "When they see a woman's breast, they see a breast — regardless of what it's being used for."

Babytalk editor Susan Kane said the mixed response to the cover clearly echoes the larger debate over breast-feeding in public. "There's a huge puritanical streak in Americans, and there's a squeamishness about seeing a body part — even part of a body part."

"It's not like women are whipping them out with tassels on them!" she added. "Mostly, they are trying to be discreet."

Kane said that since the August issue came out, the magazine has received more than 700 letters — more than for any article in years.

"Gross, I am sick of seeing a baby attached to a boob," wrote Lauren, a mother of a 4-month-old.

The evidence of public discomfort isn't just anecdotal. In a survey published in 2004 by the American Dietetic Association, less than half — 43 percent — of 3,719 respondents said women should have the right to breast-feed in public places.

The debate rages at a time when the celebrity-mom phenomenon has made breast-feeding perhaps more public than ever. Gwyneth Paltrow, Brooke Shields, Kate Hudson and Kate Beckinsale are only a few of the stars who've talked openly about their nursing experiences.

The celeb factor has even brought a measure of chic to that unsexiest of garments: the nursing bra. Gwen Stefani has been seen sporting a leopard-print version from lingerie line Agent Provocateur. And none other than Angelina Jolie wore one proudly on the cover of People. (Katie Holmes, meanwhile, suffered a maternity wardrobe malfunction when cameras caught her, nursing bra open and peeking out of her shirt, while on the town with husband Tom Cruise.)

More seriously, the social and medical debate has intensified. The U.S. Department of Health and Human Services recently concluded a two-year breast-feeding awareness campaign including a TV ad — criticized as over-the-top even by some breast-feeding advocates — in which NOT breast-feeding was equated with the recklessness of a pregnant woman riding a mechanical bull.