Remember any smart kids in high school whose grades plummeted when they discovered the opposite sex? Turns out there is data to support this stereotype.

In an article in the American Economic Journal: Applied Economics, researchers found that the greater a student's proportion of opposite gender school friends, the lower their high school grade point average. The study pointed at impacts on focus and attention, both inside and outside the classroom.

Why does it matter? Relationships are an important part of the growing process, but be wary of an unintended side effect they can have on academic performance.