Your smartphone may be causing you to grow horns—calm down, you’re not going to turn into a rhino anytime soon. More young people are developing a “horn-like” bone growth at the back of their skulls because they’re craning their necks toward their devices, according to a study from the University of the Sunshine Coast (USC).

The study was released in 2016 in the Journal of Anatomy, but resurfaced after the BBC and other news outlets wrote about it. “We hypothesise that the sustained increase load at that muscle attachment is due to the weight of the head shifting forward with the use of modern technologies for long periods of time,” Dr. David Shahar said in a statement on USC’s website.

More than 200 18- to 30-year-olds had their skulls x-rayed for the study, and 41 percent of them had lumps that looked like horns. The “horns” are actually enthesophytes, whcih are bony projections found at the end of ligaments or tendons. You can take a look here.

Don’t freak out too much, the projections are not uncommon—humans tend to develop them over many years, but not until they’re much older. That’s why scientists are somewhat alarmed to find so many of them in young people.

Furthermore, the “horns” are typically only a few millimeters long, maybe up to 9 mm, but the researchers found one that was 35.7 mm long, and several others in the low- to mid-20 mm range. In fact, a 2018 follow-up study found that young adults had longer “horns” than the older population.

So what do smartphones have to do with all this? “Shifting the head forwards results in the transfer of the head’s weight from the bones of the spine to the muscles at the back of the neck and head,” Shahar said on USC’s site. “The increased load prompts remodelling on both the tendon and the bony ends of the attachment.”

In other words, your mother was right: good posture is key. “The thing is that the bump is not the problem, the bump is a sign of sustained terrible posture, which can be corrected quite simply,” USC Associate Professor Mark Sayers said on the college’s site.