Hereditary conditions is a a condition your pet is genetically predisposed to because of its breed.
Think of things like hip dysplasia in large-breed dogs, or brachycephalic airway syndrome in flat-faced breeds like pugs and bulldogs. Both are common examples. These aren't necessarily present at birth; they can develop later, but the breed makes them far more likely.
Insurers handle hereditary conditions differently. Some cover them under their accident and illness coverage, while others specifically exclude or cap them (give them a sub-limit), and a few use a flat “age-of-pet cutoff” (e.g. excluded if it occurs within the first 3 years of life) rather than testing against when the policy started. This matters a lot more for some breeds than others, which is why it's worth checking directly against your pet's breed.
If you own a breed that is prone to hereditary conditions, like German Shepherd, French Bulldog, British Shorthair or Ragdoll, this is one of the categories most worth checking closely when you compare. As FurWise gathers more breed data, we will add more detail to our comparison tool to better reflect hereditary condition exclusions.