The YTCA is the parent breed club to AKC--in short, they wrote the standard adopted and used, etc. There is a very strict criteria and list of requirements that have to be met in order to become a member. (Visit their site for more info.) There actually used to be a few YTCA members here--4 that I can think of off the top of my head--but they rarely post anymore, which is very unfortunate.
That is not to say that all YTCA members are perfect (really I can't say, I have not met all of them) or that non-YTCA members/breeders or even non-YTCA referred breeders are bad...it just means they aren't members.