(KARE) - You may have caught wind of this on social media -- something called "thigh gap." Some girls have glorified thigh gap by posting photos of thighs so thin -- they don't touch when their feet are put together.
Doctors warn very few women have the bone structure for thigh gap to naturally occur.
"It's very rare that naturally or healthfully a woman could have this type of body shape," psychologist Heather Gallivan said. "So what is happening is adolescent girls and young adult women are going to extremes with diet and exercise to achieve this."
Gallivan the quest for thigh gap can lead to an eating disorder.
She urged parents to talk to their daughters and to assure them thighs that touch are good.