One Point Perspective Distorted Grid

In the one-point perspective grid, the grid squares seem distorted. Instead of looking like squares in perspective, they look like rectangles, longer in the direction of the perspective lines. If anything, the perspective should be making them contract in that direction, not stretch. As a test, I tried creating a perfect square and then attaching it to a plane. Sure enough, it no longer looked square, but stretched. Is there a way to correct this?