I finished reading a book about genetics and it went into details about the messed up family tree of the Hapsbergs and the illnesses they suffered. Were they aware that the illness and the inbreeding were related? Also, how were they viewed by other Royal families? While inbreeding happened in other royal families, did contemporaries see the Hapsbergs as unusually inbred?
I actually have two past answers dealing with Hapsburg inbreeding:
Habsburgs and Their Reputation
Did European nobility just not realise the damage all that inbreeding was doing to them?
Both of these are a bit more about problematizing the idea of Hapsburg inbreeding than a direct response to how much they were aware of the dangers, however.