Guest Contributor

A few weeks ago, my 13-year-old daughter brought up the issue of the “thigh gap.”

A thigh-what? I thought. I Googled it and was appalled by the latest teenage girl obsession: having ultra-skinny thighs, so much so that one can see a space in between them when feet are touching (hence, the gap) is a trait many teenagers now covet. Of course, for many, this idealized gap is physically impossible to attain. (Still, I must admit to checking in the closet mirror to see if I had one.)

topgold/flickr, creative commons

I was relieved when my daughter said she found the trend unhealthy. At the same time, she said, it’s unavoidable.

“You hear about it from your friends, it just travels,” she says. “Usually when you first find out about the thigh gap, the normal instinct is to Google it and one of the things that comes up is Tumblr and you get these crazy blogs on how to get a thigh gap and how to diet so you get it.”

(It's true, some of these sites are a parent's nightmare, from Cara’s Thigh Gap on twitter, which I'm not even linking to it because of the inappropriate content, to less-bad-but-still-troubling Operation Thigh Gap. Even this level-headed wiki-how is anxiety-producing, in that it confirms the ubiquity of the trend.)

It’s a tough world out there for our teens. We bombard them with conflicting messages to stay fit and be healthy (see Michelle Obama) while at the same time asking them not to get too neurotic about their body image. Some of us mothers send mixed messages too. What matters is how beautiful you are on the inside, we tell them, yet we work out and order salads for dinner

and clearly care about the way we look, and our girls know it.

The pressure to be thin is nothing new. Generations of women have grown up yo-yo dieting, bingeing and purging since their teens. But what feels very different to me now is the constant barrage of images and opinions that’s being fed into our daughters' brains in addition to the traditional, more passive pressures coming from magazines and TV.

That extra layer of influence is coming from the Internet and social media, and the way I see it, it’s like peer pressure on steroids — a vehicle for immediate feedback about you, the way you look, or what you think of others. And those opinions are so widely broadcast. Depending on a teen’s social media prowess, that can mean hundreds, even thousands of extra eyes.

That got me wondering whether social media has a different impact on a teenager’s self-worth and body image than TV or magazines, where it’s more evident that what you see is an idealized version of what’s normal. The obvious concern with social media-fueled phenomena like the thigh gap is that the pressure to have one might lead some girls to develop severe body dissatisfaction or, even worse, eating disorders.

So I spoke to Jessica Suisman, a doctoral student in the department of psychology at Michigan State University and the lead author of a study looking at the genetic factors underlying eating disorders and body dissatisfaction. I asked her if researchers knew what is the impact of social media on body image issues in young girls.

She says nobody really knows yet whether social media is more powerful than other media, since the research on this is just getting started. But one trend seems to be emerging: social media appears to be breaking down old models of analyzing factors that cause eating disorders.

Suisman talked about the "Tripartite Model," which has been around since the 90s and describes three primary influences on the development of eating disorders and a person’s preoccupation with the “thin-ideal” (the extent to which a person identifies with the cultural ideal of thinness). Those three main influences:

1. Relationships with peers

2. Relationships with parents and, of course,

3. The media, which has traditionally been seen as TV, images from magazine and, lately, the Internet.

But, says Suisman, social media seems to be blurring the line between the previously distinct effects of peers and media. She told me:

It’s no longer media and peers; they’re now kind of combined into one thing...like Facebook. And we also know from just research on people’s behavior on Facebook that the types of pictures that people post, or the way that people present themselves on Facebook is sort of an ideal. People are posting edited pictures or only the pictures where they look the best so that when you are comparing yourself to somebody on Facebook you might not realize you’re comparing yourself to an ideal.

It will be a while before we really understand how fads like the thigh gap truly affect our daughters. In the absence of solid research, I’m willing to bet the effect of social media is much bigger than magazines or TV, at least from hearing my daughter’s own words: “When you open a magazine you can feel a little less confident by looking at the perfect photoshopped model, but at the end of the day you realize it’s not realistic at all and that they are airbrushed. But when you see it on social media and in your group of friends it’s more realistic and you’re more influenced.”

But my daughter also brings up a good point, which is that even though she and her friends know about the thigh gap, she doesn’t know anyone who is actively dieting or starving herself in order to achieve one. Somehow these influences affect some girls profoundly, while not others. According to Suisman’s work, some of this could be due to genetics.

In her recent paper, published along with senior investigator Kelly Klump, who is the Co-Director of the Michigan State University Twin Registry, it became clear that genes influence how people are affected by pressures to be thin. Here's what Suisman said:

Across the board we found that identical twins tend to be much more similar to one another than fraternal twins in terms of their levels of disordered eating and thin ideal internalization, and this suggest genetic influences on these phenotypes since identical twins share a much larger proportion of their genes than fraternal twins. Our group has one adoption study as well, where we looked at siblings who were both adoptees, so they weren’t genetically related at all compared to siblings who were regular biological siblings, and we found the same sort of pattern—the regular biological siblings were more similar in their disordered eating than non-related adopted siblings.

This is a real wake-up call for me, and probably many parents. It makes us look at ourselves as mothers and parents, and our own relationships with body image, as we try to decipher our daughters.

So, parents: are any of you dealing with these issues at home? Have your daughters also brought up the thigh gap issue, and how did you handle it? Please let us know.

Sylvia Pagán Westphal has a Ph.D. in genetics and is a health writer and mom of five kids ages 4 to 13.