Pick your parents well.
The pec major has different fiber orientations, with clavicular fibers and sternal fibers. Incline places more emphasis on the clavicular fibers which is because of the orientation, or line of pull. Less are aligned in this array, which is why most people tend be weakest in incline, then flat, and strongest in decline bench, where the greatest number of fibers are aligned in opposition to the resistance. You can change the emphasis but not the shape. The pec minor is commonly misconstrued, it does almost nothing in bench movements, and is a shoulder stablizer and runs from the sternum to the clavicular process. It depresses the scapula and rotates it, but that's it. If you have a lagging bodypart, work it as hard as you can, but know that while it may grow, youare limited by your genetics and the shape it had when you were born.