Anybody know exactly how it is passed or is this not known yet? I have heard of dogs having it, being bred, inbred, linebred on and still produce fine dogs that are healthy. Meanwhile there are cases where the dog doesn't have a one nut dog anywhere close in the ped yet it still is born with the defect. Seems kind of unpredictable and sporadic, not like what the vet says...along the lines of "if u breed him, u will have a bunch of one or no nut dogs".