The last few years have been tough ones for Barbie. Sales have declined significantly, dropping 16 percent in 2014 alone. In an effort to jumpstart the sagging brand, Mattel has launched a new marketing campaign called, “Imagine the Possibilities.” The signature ad for the campaign features little girls in professional roles in otherwise normal settings: a girl professor in front of a lecture hall, a girl veterinarian attending to a sick cat, a girl coach barking orders at a men’s soccer team. Dressed in sports garb, she blows on her whistle and yells, “Knees up! Like a unicorn. Higher! Higher!”

The ad ends with a little girl playing with several Barbies on the floor of her room, and the big reveal: The scenarios were all in the girls’ imaginations. The following tag line then appears: “When a girl plays with Barbie she imagines everything she can become. You can be anything.”

If only that were how it worked. A 2014 study of 4-to-7-year-old girls found that playing with Barbie actually limited girls’ perceptions about what they could be in the future. Compared to girls who played with Mrs. Potato Head, girls who played with fashion Barbie identified a greater number of careers as ones they could not do when they grew up. The same pattern emerged even when girls played with Doctor Barbie.

Why would this be? A few studies suggest that Barbie’s particular physical appearance—her sexualized body, her tight jeans (for Doctor Barbie), or her minidress (for Dentist Barbie)—may have something to do with the dampening of little girls’ career aspirations. There’s a plausible pathway for this: Maybe it’s because playing with sexualized and distortedly thin dolls makes girls think more about what they look like and less about their aspirations.

One study examining this connection between Barbie and body image found that after hearing a story illustrated with pictures of Barbie, young girls expressed higher levels of dissatisfaction with their bodies and a greater desire to be thin than girls who heard the same story but saw images of a full-bodied doll. Another study that looked at how much food girls ate after playing with different-sized dolls found that girls who were assigned to play with average-sized dolls ate more food than girls who were assigned to play with Barbie. Disturbingly, a study of more than a hundred girls, ages three to six, found that almost a third of them would change something about their physical appearance if it were possible, about a third reported that their ideal figure was thinner than their current size, and about half of the girls said they worried about being fat “sometimes” or “almost always.”

Americans live in a culture infused with sexualized images of women and girls. Even Halloween costumes for little girls are sexy. This is not harmless. The messages these images send—that a thinner, sexier appearance is better—get internalized and adopted by girls themselves. For example, a study of 6-to-9-year-old girls found that when asked to pick the paper doll they would like to look like, the girls overwhelmingly picked the sexualized doll over the non-sexualized one for their ideal self.  

And this is where real damage is done. Studies repeatedly find that when girls engage in body-objectification (monitoring and working on one’s appearance to increase attractiveness) or self-sexualization (believing that being sexually attractive to men is an important part of their identity) there are negative outcomes. Girls who objectify their bodies more have lower self-esteem and higher rates of depression. Other research has found that self-sexualization can undermine achievement. Girls with higher levels of internalized sexualization get worse grades and lower standardized tests scores.   

Which brings us back to Barbie. The ubiquitous sexualization of girls and women is not solely Barbie’s fault, of course. Barbie is but one cog in very large media- and society-fueled wheel. But Barbie is a big cog. It’s estimated that 90 percent of girls own one.

Mattel’s tag line says one thing, but its product sends a different message: Be anything you want to be. Just be sure to look beautiful and sexy doing it. Spend a lot of time thinking about what you look like and always monitor how much you eat. This may mean you accomplish less in your life. But for a girl, having other people think you are attractive is a really important goal.