Inescapable media images of sexed-up girls and women posing as adolescents can cause psychological and even physical harm to adolescents and young women, a study in the US has warned.

The pressure of what experts call "sexualization" can lead to depression, eating disorders, and poor academic performance, said the report, released Sunday by the American Psychological Association.

"Sexualization of girls is a broad and increasing problem and is harmful to girls," it concluded.

Adult women dressed as school girls in music videos, bikini-clad dolls in hot tubs, and sexually-charged advertisements featuring teenagers were among the many examples cited.

Such omnipresent images -- on television and the Internet, in movies and magazines -- can also have a negative effect on a young girl's sexual development, the study cautioned.

Based on a comprehensive review of academic literature, the 66-page report noted that young adolescents and girls were particularly at risk "because their sense of self is still being formed."

School performance can also suffer. In one experiment cited, college-aged women were asked to try on and evaluate either a swim suit or a sweater. While they waited for 10 minutes while wearing the garment, they completed a math test.

"The results revealed that young women in swimsuits performed significantly worse ... than those wearing sweaters. No difference were found for young men."

The study, which includes numerous recommendations for concerned parents, coincides with a growing wave of public concern about the impact of highly sexed imagery.

The fashion world has been in turmoil since public authorities in Madrid banned under-weight and under-age models from catwalks last year.

The Italian government and two top fashion associations followed suit, signing a code of ethics in December after top Brazilian model Ana Carolina Reston died of heart failure weighing only 40 kilos (88 pounds).

In France, Health Minister Xavier Bertrand, concerned about the rise of eating disorders such as anorexia and bulimia, recently asked a panel of experts to create a similar voluntary code for advertisers and clothing designers on how the female body should be portrayed.

Sunday's study said sexualization occurs when "a person's value comes only from his or her sexual appeal or behavior," when sexuality is inappropriately imposed, or when a person is sexually "objectified."

Looking at popular music videos, the authors quoted songs by the Pussycat Dolls, Kid Rock, and 50 Cent, emphasizing lyrics that they suggested sexually objectified women.

The report said that "sexualization of women is particularly prominent in advertising," and singled out beer commercials as a major offender.

Also cited was a Skechers shoe ad that features pop singer Christina Aguilera dressed as a school girl in pigtails, with her shirt unbuttoned while licking a lollipop.

The popular Bratz dolls, the study noted, depict "girls marketed in bikinis, sitting in a hot tub, mixing drinks, and standing around, while the 'Boyz' play guitar and stand with their surf boards," it said. The dolls come dressed in miniskirts, fishnet stockings, and feather boas.

The report called on parents to take a more active roll in helping to shape the sexual self-image of their children, and to exert consumer pressure on manufacturers and advertisers.

In the United States, the sexualization of young girls became an issue of public debate after the 1996 murder of JonBenet Ramsey, a six-year old beauty pageant contestant who put on makeup and adult clothes.