A survey of 50,000 adults finds 70 percent of female respondents desiring more ample or rounder breasts -- even though the majority of male respondents say they are perfectly happy with their partner's breast size.

Men have their own insecurities: The same survey finds nearly half of males wishing for a larger penis. At the same time, however, 85 percent of females say they are "very satisfied" with their partner's endowment.

"The picture this paints for us is that people are way more self-critical of themselves than they need to be. In reality, their partners are generally quite satisfied with them and their physical attractiveness," said David A. Frederick, a researcher in body-image issues at the University of California, Los Angeles.

Frederick is lead author of the two studies, each based on data collected from a 27-item MSNBC/Elle magazine online survey on body image, posted on both organization's Web sites for a two-week period in February 2003.

More than 50,000 adults averaging between 33 to 36 years of age responded to the anonymous survey. The vast majority (98 percent) of respondents filled out the survey while visiting the MSNBC site.

Frederick believes Americans of both genders face incredible media and social pressures to conform to nearly unattainable physical ideals.

For women, "the popular Barbie doll, with her slender body, narrow hips and large breasts represents this ideal," his team wrote in a study presented Friday at the American Psychological Society annual meeting, in Los Angeles.

Unfortunately, Barbie's proportions are "so extreme that it is estimated that just one in every 100,000 women possesses her body type," the researchers added. The drive to achieve an ideal feminine body type is helping fuel a continuing boom in cosmetic surgery, experts say. According to the American Society of Plastic Surgeons, more than 264,000 women underwent breast augmentation in 2004 alone.

While men may feel less pressure than women to attain the perfect physique, one body part, especially, remains a focus of concern. According to Frederick, previous studies have shown that men overwhelming link the size of their penis to their sense of masculinity, and often worry that their partners are dissatisfied with their endowment.

But how valid are these fears? According to Frederick, the MSNBC/Elle survey results suggest many Americans are their own worst critics.

When asked about their breasts, seven out of 10 women surveyed expressed dissatisfaction with either size (usually "too small") or shape ("too droopy"). Women in the youngest age group (18 to 25) were most likely to be content with their breasts (33 percent), but they were also the most likely to desire bigger breasts (37 percent), according to the researchers. As women aged, concerns turned from breast size to dissatisfaction with shape, or "droopiness."

Males were much less critical when it came to judging their wife's or girlfriend's breasts, however. Overall, "a majority of men (56 percent) were satisfied with their partner's breasts," the researchers concluded. "A mere 20 percent of men in our sample wished their partner had larger breasts."

Frederick acknowledges that previous, smaller studies have suggested that men view large breasts as "ideal." That's because those studies have usually asked men to simply pick their favorite from a series of photos, he said. "What we wanted to get at in this study was how satisfied men are with their partner, because it could be that men find a variety of breast sizes to be attractive, regardless of what they rate as ideal."

For their part, women appear to be very accepting of male endowment, the survey found. But even though 85 percent of women said they had no problem with their boyfriend's or husband's size, nearly half (45 percent) of all males surveyed said they wished for something larger. That number rose to 54 percent among males who rated their penis length as just "average."

"The really good news for men, though, was that only 6 percent of women considered their partner 'smaller than average,'" Frederick pointed out. (For the record, Frederick said the most reliable U.S. studies peg "average" penis size at an erect length of approximately 5.5 inches.) The full results of this study will be published soon, Frederick said.

"What's so interesting about these studies is the way women and men see themselves," said Courtney Fea, another body-image researcher and social psychologist who presented her own study Friday at the Los Angeles meeting. "Even though many feel inadequate, they really don't understand that others see them as quite adequate," she said.

Her study points to one obvious remedy for some of this insecurity: compliments.

Focusing on college-age women, her team at Kansas State University had participants engage in an evaluation session that included a "Self-Objectification Questionnaire" aimed at spotting women with an unhealthy body-image fixation.

At the end of the session, a female researcher casually offered the women one of three remarks: "Thank you for participating," (neutral); "You are a nice-looking person" (body compliment); and "You sound like a nice person" (character compliment). The women were then retested using the Self-Objectification Questionnaire.

"Women who looked at themselves first as bodies had less shame and became less concerned about their appearance after a compliment," Fea said. "And the interesting finding was that it didn't matter what kind of a compliment it was -- whether it was about their body or character." On the other hand, compliments had little impact either way on shame or depression in women without major body-image concerns, Fea said.

The take-home message? "If you're thinking about complimenting someone, go ahead and do it," Fea said. The study wasn't designed to test how long the feel-good effects of a compliment can last, she said, but saying something nice certainly can't hurt. "It not only makes them feel better, but it'll probably make you feel better, too."

Frederick agreed that people shouldn't take it for granted that their partner knows exactly how much they are valued.

"On both sides of the coin, men and women should express themselves, and if they are satisfied with their partner's appearance, this needs to be communicated," he said. That kind of communication could help dispel fears that specific physiques or body parts aren't up to par, he said.

It might even spice up relationships, Frederick said. "The more confident your partner is, the healthier they'll be, including being more interested in sex. There can be all kinds of positive outcomes."