You’ve Come A Long Way, Baby?
The mass media, especially children’s television, provide more positive role models for girls than ever before. Kids shows such as Dora the Explorer, Canadian Geographic for Kids, and The Magic School Bus feature strong female characters who interact with their male counterparts on an equal footing.
There are strong role models for teens as well. A study of the media favoured by teenage girls discovered that a similar proportion of male and female characters on TV and in the movies rely on themselves to achieve their goals and solve their own problems. (The one discrepancy was in the movies, where 49 per cent of male characters solve their own problems, compared to only 35 per cent of their female counterparts.)  Television shows like Bones and Battlestar Galactica and computer games such as Mirror’s Edge and Portal star girls and women who are physically assertive and in control. And of course, Lisa has been acknowledged as the brains of the Simpson family since the start.
Despite the progress that has been made there is a long way to go, both in the quantity of media representations of woman and in their quality.
In terms of quantity, the media is still a long way from reflecting reality: women represent 49 per cent of humanity while female characters make up only 32 per cent of the main characters on TV, as shown by a broad survey done in 2008 by Doctor Maya Götz of the International Central Institute for Youth and Educational Television.  This study measured the representation of male and female characters in nearly twenty thousand children’s programs in 24 different countries. The media industry justifies this disparity by arguing that it is easier for girls than boys to identify with characters of the opposite sex. Götz argues that this argument reverses cause and effect, saying that it is the lack of female characters on TV is what leads to the higher popularity of male characters.
So far as quality is concerned, the media still conform to a stereotyped image of women. Götz’s study identifies a number of sexual stereotypes found around the world: in general, girls and women are motivated by love and romance, appear less independent than boys, and are stereotyped according to their hair colour – blonds fall into two categories, the “girl next door” or the “blonde bitch,” while redheads are always tomboys – they are nearly always conventionally attractive, thinner than average women in real life, and heavily sexualized.
Magazines are the only medium where girls are over-represented. However, their content is overwhelmingly focused on topics such as appearance, dating and fashion. 
Media, Self-Esteem and Girls’ Identities
Research indicates that these mixed messages from media make it difficult for girls to negotiate the transition to adulthood: Girls’ confidence frequently drops in the pre-teen years as they begin to base their feelings of self-worth more and more heavily on appearance and weight. 
Carol Gilligan was the first to highlight this unsettling trend in her landmark 1988 study. Gilligan suggests it happens because of the widening gap between girls’ self-images and society’s messages about what girls should be like. 
Children Now points out that girls are surrounded by images of female beauty that are unrealistic and unattainable. And yet two out of three girls who participated in their national media survey said they “wanted to look like a character on TV.” One out of three said they had “changed something about their appearance to resemble that character.”
In 2002, researchers at Flinders University in South Australia studied 400 teenagers regarding how they relate to advertising. They found that girls who watched TV commercials featuring underweight models lost self-confidence and became more dissatisfied with their own bodies. Girls who spent the most time and effort on their appearance suffered the greatest loss in confidence.  (For more on this topic, see Body Image - Girls.)
Eroticization of Young Girls
In addition to being under-represented, women are equally misrepresented: the hypersexualization of very young girls, most notably in fashion and advertising, is a disturbing trend given that these stereotypes make up most of the representations of themselves which girls and women see in the media. The pressures on girls are exacerbated by the media’s increasing tendency to portray very young girls in sexual ways. The fashion industry is a major driver for this trend, commonly presenting 12- and 13-year-old girls as if they are women. Camera angles (where the model is often looking up, presumably at a taller man), averted eyes, wounded facial expressions, and vulnerable poses mimic the visual images common in pornographic media.
In 2011, images of 10-year-old Thylane Loubry Blondeau appearing in French Vogue magazine fuelled debate amongst child development experts and government on what restrictions should be made relating to sexualisation of children in the media. 
The most cursory examination of media confirms that young girls are being bombarded with images of sexuality, often dominated by stereotypical portrayals of women and girls as powerless, passive victims.
As these girls become teenagers, many choose to tune out, but others maintain a hungry appetite for these messages. As Shawn Doherty and Nadine Joseph note, those who continue to consume media images are strongly influenced “by stereotypical images of uniformly beautiful, obsessively thin and scantily dressed objects of male desire. And studies show that girls who are frequent viewers have the most negative opinion of their gender.” 
 “A Different World: Children’s Perceptions of Race and Class in Media,” Children Now, 1996
 Götz, Maya. Children’s Television Worldwide: Gender Representation. International Central Institute for Youth and Educational Television, 2008.
 Nancy Signorelli, “A Content Analysis: Reflections of Girls in the Media,” The Kaiser Family Foundation and Children Now, April 1997.
 Baldwin, S. A., & Hoffmann, J. P. (2002). The dynamics of self-esteem: A growth-curve analysis. Journal of Youth and Adolescence, 31, 101–113.
 Gilligan, C., Ward, J. V., & Taylor, J. M., & Bardige, B. (1988). Mapping the moral domain: A contribution of women’s thinking to psychological theory and education. Cambridge, MA: Harvard University Press.
 Hargreaves, D., & Tiggemann, M. (2002). The effect of television commercials on mood and body dissatisfaction: The role of appearance-schema activation. Journal of Social and Clinical Psychology, 21, 328–349.
 Bailey Review of the Commercialisation and Sexualisation of Childhood: Final report published. 2012. http://www.education.gov.uk/inthenews/inthenews/a0077662/bailey-review-of-the-commercialisation-and-sexualisation-of-childhood-final-report-published
 Doherty, Shawn and Nadine Joseph. From Sidekick to Superwoman: TV’s Feminine Mystique. Children Now, 1995.