Since the first appearance of white dogs in the breed some 35 years ago, every dog descended from that original breeding has received a special AKC designation (Z list) if they are registered.
The first recorded white Doberman Pinscher was a female named Shebah whelped in 1976. She managed to be registered with the AKC despite being an albino but no albinos can be registered today. Thinking they were onto a good thing, the breeders bred the female as soon as she was able and eventually put her to her own son (which guaranteed that both parents carried the recessive gene). She then managed to have white puppies. All white Dobermans, and Dobermans with a "Z" in their AKC registration numbers, are thought to be descended from Shebah.
This happened because of pressure from the DPCA to insist that "Z" be placed in their registration to indicate this. They also wanted to disallow these dogs to have litters that could have full AKC registration. AKC allowed the "Z" to be put into their registration numbers, but did not go along with disallowing full AKC registration to offspring, but left that up to the breeders. Disagreement about this is kind of interesting. I haven't found out what the details were.
The "Z" has a stigma associated with it, because albino animals have many health problems, and if your doberman has a "Z", there's thought to maybe be something wrong with him or her...and insistence on not letting them have pups--spaying and neutering are demanded for them on the doberman forums. Pure bred dogs in general have more health problems than mutts, that is why their life expectancies are years less. However, other health issues with dobermans, especially dilutes, are also possible serious issues. I know, I just went through a major ordeal with a blue doberman that cost me thousands of dollars. I don't understand the special insistence that a registered doberman with a "Z" should never be bred, but no mention of, or AKC registration indication of ancestors of non Z-factored dobermans with major health issues.
"People who know" on this and other forums about this, are not presenting facts and figures that bear out what they claim, despite bragging about decades of experience. Do they have experience in breeding dogs with a "Z" in their AKC registrations, and comparing with those who don't?
I just think there is something amiss in thinking breeding a doberman with a "Z" in their AKC registration is detrimental to the doberman breed. Especially if they have a genetic test that indicates that the albino gene is just not there.
(reading back, gee, I might be banned from this forum!)