Not true, my chest genetics are crap, my chest only grew once I concentrated on the bench, after a chest session only my chest would be sore, my delts or triceps would not be sore at all
I cant even feel my chest when I flat bench's I just do then for delts, same with flat flys, as soon as my arms get just past parallel with the bench coming up the entire pec relaxes
I dropped all excercises that I cant feel the muscle work now, my chest session consists of cable crossovers , pec dec and machine declines, and then press with 1 dumbbell holding with both hands and push from middle of chest.