As Dr. Jerome Bell so succintly put it: "It is the varied opinion of breeders as to what constitutes the ideal dog, and their selection of breeding stock that maintains breed diversity." The current problem of erupting genetic disease, as far as it applies to pedigrees & breeding, reflects two trends. One is a problem of the "Matador," that is the "Popular Sire Syndrome." When all run to breed to a winning dog, or some dog or bloodline, (for whatever reason, be it convenience, ignorance or perceived value), genetic diversity can be lost. But indiscriminate universal assortative matings is not the answer to this problem & can actually reduce genetic diversity in the breed by "homogenizing" gene pairs across the whole breed. Outcrossing cannot solve the problem of genetic disease anymore than inbreeding is the cause of it. However "type" breeding, that is, the mating of two animals of similar looks, not similar pedigrees, CAN effect one particularly good thing which is the take-home message of "diversity breeding": since the number of genes involved
with creating a certain "look" are much less than the likely number doubled up with linebreeding (esp. "blind" linebreeding, time and again, on some "famous" relative), the loss to the breed of heterozygousity is slowed and the individual dogs are arguably more safe from various line defects...while still having "type."

The other major problems in dogs today as to disease has little to do with hobby ("show") breeders & is largely a problem of casual breeding. Casual breeding produces more than three-quarters of all registered dogs in the USA & assumably (nearly) 100% of mixed-breed litters. as a result of the low investment & high profitibility (not just in money) that dog breeding brings to the average American household. There is a clear cultural support for anyone & everyone breeding their own pet, and this liscence runs counter to the serious study & self-education process necessary to breed dogs well enough to avoid bad temperaments and worse health problems. That so many pet buyers do not clearly see this means casual breeders are able to enjoy having litters, & be certain of sales, even if their only credentials are that they love their dogs. These litters, despite the buying public's perception & causal breeder's claims, suffer often from major genetic problems they continue to pass along _and_ they are often indiscriminatly inbred, as they are usually exclusively local (or narrowly regional) breeding programs, often with the whole breeding population sustained by a couple of friends. What is needed is educated, dedicated, honest breeders & scrupulous selection. Breeders need to know the dogs they are using in their breeding programs & need to know them intimately. Each needs to have a clear priority of what they cannot live with & what they cannot live without. (And ideally each would clearly announce this somehow so others are clear on their priorities before they buy or breed from them.) A variety of styles, of lines, of sub-populations, criss-crossing, seperating & then, again, coming together in a wonderful breed mosaic, is the best recipe for maintaining type, health, temperament _ &_ diversity in any breed. And for all that "diversity" is a buzzword of fashion right now, it isn't at all a new idea, just a new term for the notion of having a variety of bloodlines within a breed. (Note also that diversity does not necessarily equal outcross.) What is needed in most all breeds is for more good dogs to be rooted out & recognised, despite their lack of glamour & dazzling ads. (That & for America to get serious about dog breeding & treat it with the gravity it deserves.) It would also help if more folks would work together to preserve bloodlines and create new ones by judicious crosses, so that variety would be preserved. For this more people will have to get educated about the history and styles of their breed; too many today simply breed to some current fashion )or market!), oblivous to the fact what they are seeing is simply fashion and not "the" standard for the breed.