I have no issue with being up front about the fact that in my 20 years of breeding miniatures(never more than 4-5 foals/year, and usually, not that many), I had one dwarf born.
I never again bred EITHER sire or dam; at the time, I felt my best solution was to DONATE both to an 'endangered youth' program in a neighboring state, as they had a well-established program using horses for the youth to show and train. I did not geld the stallion, because at the time, they did not breed(I later found out that they did breed the horse ONCE, that I have been able to find out--I only hope it wasn't more--and if I had it to do over again, I'd geld the stallion first. I fully disclosed that this pair had been responsible for the production of a dwarf, and told them neither should be bred again--the director of the program agreed at the time, but of course, I don't know whether he kept his word. I wish I could have afforded to have the mare spayed, but it wasn't an option.
I also donated the last daughter of the stallion to their program, because I knew she could be a carrier. I didn't feel right about selling anything that I KNEW COULD BE a carrier. I kept NOTHING related to either horse; the maternal granddam of the dwarf (I'd bred and raised the dam)-a very nice mare--has thankfully never again produced-she is a wonderful 'teacher' of youngsters, instead(under her current owner.)
I took a sizable financial hit on the sire-he cost me $5000, a sizable sum for me. But, it was the ONLY ethical course, I believe.
Because of the above facts, though, my honest answers to the poll might 'skew' the results a bit, as I DIDN'T sell the sire or dam, nor geld the stallion, but DID effectively take them out of predictable production!
My personal opinion, based on a very basic level of study of Mendelian genetics, is that carriers are NOT 'rampant' within miniature horses; if they were, I believe we would have MANY more dwarves than we do. However, I also feel that many carriers are 'out there' that shouldn't be, because too many are too willing to continue to breed known producers, be they sire or dam. IMO, it is NOT enough to just 'never breed those two together again', but that is the path many take, seeming to think that 'takes care of the problem'...yet with our current lack of factual knowledge, the only thing that will ENSURE that a horse that has been sire or dam to a dwarf never produces another is to NEVER AGAIN breed that sire or dam to ANYTHING else.
I wholeheartedly support the research being done, and would have donated my little dwarf in a heartbeat, if I had her now and she fit John's parameters(and she was a DEAR little thing, and her euthanasia was a heartbreaking occasion, but it contributed NOTHING to answering the questions of the causes of dwarfism, and it might have, could she have been a research subject!) With proper knowledge, it *might* even be possible to CONTROL dwarfism in a manner similar to that of CID(SCID?) in Arabians--that is, by testing, then allowing ONLY the breeding of a 'clear' to a 'carrier', but NEVER a 'carrier' to a 'carrier', as is my understanding of their registry's approach...?