Our vet had just returned from a conference on LS the day before I visited him, like two, maybe three years ago. He gave me a paper with infomation on LS and it stated that yorkies are
1200 times more likely to have or get liver shunts than any other breed. Even if both parents tested negative, you may still get a LS puppy, or they
might develop it as an adult. If that's the case, all YT breeders are playing Russian Roulette.
It was only a month later when our son was concerned about his Corgi not eatting. I started telling him about LS and it turned out his Corgi had LS and they lost him.
I'm sure I'm going to get some reation with this.....

When adults breed (been around dogs too long......) we all hope for a healthy baby.

Sometimes that is not the case and there may be siblings that are fine. And sometimes there is no logical explaination for the heriditary disease but science tells us it had to be there, somewhere. And as we grow old, we develop deadly ailments.

So should we not breed (have children) in the first place
just in case? Yes, we should be cautious and responsible, but sometimes all the caution in the world won't change the outcome.
Just my thoughts...........
Linda