Hydraulic fracturing, the technological advance that fueled the U.S. energy boom, also boosted the number of high school dropouts, according to a report by the National Bureau of Economic Research.

“Who Needs a Fracking Education?” found that fracking helped boost the demand for low-skilled labor. Boys in high school jumped at the chance to grab these jobs.

The paper’s authors estimate that without fracking the gap between male and female high school dropout rates at local schools would have narrowed by around 11 percent between 2000 and 2013. Instead, the gap remained unchanged.