If you breed APBTs without regard for their degree of gameness, their gameness will gradually be lost with each succeeding generation. This is essentially what has occurred with Am Staffs and Staffy Bulls, which for many generations have been selectively bred for appearance rather than for the invisible inner quality of gameness. In order to maintain a high degree of the desired qualities, a breeder must carefully select only those dogs that have them in the highest degree. Gameness was an extremely difficult trait to develop; it took more than a century of tiny, incremental improvements through selective breeding to produce today's APBT. Though achieved only with great difficulty, gameness is easily lost, sometimes even in the hands of good breeders. If you mate two grand champions, you will be lucky if just one or two of the pups is of the same quality as the parents. Traditonally, the job of breeders was to identify these offspring and use only them to continue the breeding program.