For almost everyone, you'll find that one leg is longer than the other. If the difference is as slight as a half centimeter you probably needn't worry, but at some point you'll want to make your bike fit. There are three major ways to adjust your bike.

If the difference is mostly in your thighs, you'll want to compensate in your crank length. It isn't easy or cheap to order an odd crank of a different size, but it will do the trick.

If your lower legs are different, the pedal cage height is the measurement to change. Shimano makes drop-center pedals, which can be fitted to some cranksets. The shorter leg uses a conventional pedal, possibly using a an adapter in the crankset.

Another option is to use orthopedic pedals set to different cage heights. France's T.A. makes a set, and a good bike shop can order them for you.